<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:f2b7db3e-2be4-4e85-8c3d-cdad107683e1,g:bcd527c7-9624-4117-8922-4ac4d7d2a1c8-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CoverPage" xlink:type="simple" xlink:href="wdc-20210402.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CoverPage" xlink:type="extended" id="ib2d03beab6e643fd9817a88090927567_CoverPage"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended" id="i53ad88bfa9e44fba9a477fee5c4a6953_CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended" id="ib77b948f276b4d2b8c8c672c3f8fee54_CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended" id="i182cfc6f78e24bdaa2b983bb0b8bde6b_CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:type="extended" id="i2c7d9b34c19342828983124950c2297a_CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended" id="i9276651449ab4d219a9ef3573a497be5_CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:roleRef roleURI="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="wdc-20210402.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="extended" id="i48fa9e07657b4f7d8c0d23cff26b75a0_CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_1c048080-b091-4e00-8da2-f1b5ff293d6d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1c048080-b091-4e00-8da2-f1b5ff293d6d" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_e101bfe6-8e12-4974-9a7d-87362751114a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_e101bfe6-8e12-4974-9a7d-87362751114a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1afc64e8-eb89-4d14-8ee1-dd4b65c12a2b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_StockholdersEquity_1afc64e8-eb89-4d14-8ee1-dd4b65c12a2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_59ab3f41-afbf-4657-bd1d-62eff0414d0b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_NetIncomeLoss_59ab3f41-afbf-4657-bd1d-62eff0414d0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansNetOfTaxWithholdings_b5be0e2a-0964-410b-b0de-d0fa1d985bf6" xlink:href="wdc-20210402.xsd#wdc_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansNetOfTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_wdc_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansNetOfTaxWithholdings_b5be0e2a-0964-410b-b0de-d0fa1d985bf6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_StockIssuedDuringPeriodValueEmployeeStockPurchasePlanNetOfTaxWithholdings_4fac7005-75a5-4c24-838e-a559963466f2" xlink:href="wdc-20210402.xsd#wdc_StockIssuedDuringPeriodValueEmployeeStockPurchasePlanNetOfTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_wdc_StockIssuedDuringPeriodValueEmployeeStockPurchasePlanNetOfTaxWithholdings_4fac7005-75a5-4c24-838e-a559963466f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_24234d3b-a708-4cf6-a31b-0946fc85b56c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_24234d3b-a708-4cf6-a31b-0946fc85b56c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_DividendsDeclared_f1d61655-f726-41da-95a2-287ad57f4cce" xlink:href="wdc-20210402.xsd#wdc_DividendsDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_wdc_DividendsDeclared_f1d61655-f726-41da-95a2-287ad57f4cce" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_bfc64a1f-f347-4992-bb5c-f373fe2234df" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_bfc64a1f-f347-4992-bb5c-f373fe2234df" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_f696dfab-87af-4559-b77f-966aeed4c796" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_f696dfab-87af-4559-b77f-966aeed4c796" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_2ed88b18-108d-46fb-b9a8-dc66f47985c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cc73ecbd-046b-4d4d-8983-4a6c5e31de55" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_2ed88b18-108d-46fb-b9a8-dc66f47985c7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4ffd33c4-9033-48f8-bfbe-cecc43229ee0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_001b8fde-3c3b-48a2-98bc-c7c417f7d8d2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_7e1e0649-7ce7-4fc7-b72c-e9b1a6c685f3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_1c048080-b091-4e00-8da2-f1b5ff293d6d" xlink:to="loc_us-gaap_StatementTable_7e1e0649-7ce7-4fc7-b72c-e9b1a6c685f3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_305aa95e-0957-4fb1-a9fe-5ada728660f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_7e1e0649-7ce7-4fc7-b72c-e9b1a6c685f3" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_305aa95e-0957-4fb1-a9fe-5ada728660f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_305aa95e-0957-4fb1-a9fe-5ada728660f7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_305aa95e-0957-4fb1-a9fe-5ada728660f7" xlink:to="loc_us-gaap_EquityComponentDomain_305aa95e-0957-4fb1-a9fe-5ada728660f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_305aa95e-0957-4fb1-a9fe-5ada728660f7" xlink:to="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_5d53281f-d4bd-4055-aa6d-c7b43e149208" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:to="loc_us-gaap_CommonStockMember_5d53281f-d4bd-4055-aa6d-c7b43e149208" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_a2c7c7ea-a37e-4b49-a05a-97fe710e9b0f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:to="loc_us-gaap_TreasuryStockMember_a2c7c7ea-a37e-4b49-a05a-97fe710e9b0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_51770981-5fe5-4e55-8dab-13212d4d7ae7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_51770981-5fe5-4e55-8dab-13212d4d7ae7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3bfd2a9b-fb90-448d-aee7-112953567f57" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3bfd2a9b-fb90-448d-aee7-112953567f57" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_31e420fb-d54f-422e-aed4-22e48c996bc6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f7c0cb89-7e4e-4665-88f8-6c37058d288b" xlink:to="loc_us-gaap_RetainedEarningsMember_31e420fb-d54f-422e-aed4-22e48c996bc6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d968b660-ae8b-4a94-bad2-2c4a577de0a1" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_7e1e0649-7ce7-4fc7-b72c-e9b1a6c685f3" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d968b660-ae8b-4a94-bad2-2c4a577de0a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d968b660-ae8b-4a94-bad2-2c4a577de0a1_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d968b660-ae8b-4a94-bad2-2c4a577de0a1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d968b660-ae8b-4a94-bad2-2c4a577de0a1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7ece7efe-d58a-4959-8dad-9e3c30eef33f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d968b660-ae8b-4a94-bad2-2c4a577de0a1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7ece7efe-d58a-4959-8dad-9e3c30eef33f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_3e822d59-f1d7-4f47-9b86-36e70fb940dd" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_7ece7efe-d58a-4959-8dad-9e3c30eef33f" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_3e822d59-f1d7-4f47-9b86-36e70fb940dd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/OrganizationandBasisofPresentation" xlink:type="simple" xlink:href="wdc-20210402.xsd#OrganizationandBasisofPresentation"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/OrganizationandBasisofPresentation" xlink:type="extended" id="ia772d327203c47438cce07341527c787_OrganizationandBasisofPresentation"/>
  <link:roleRef roleURI="http://www.wdc.com/role/OrganizationandBasisofPresentationPolicies" xlink:type="simple" xlink:href="wdc-20210402.xsd#OrganizationandBasisofPresentationPolicies"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/OrganizationandBasisofPresentationPolicies" xlink:type="extended" id="i5840252dc55344c18516f5fc4006f1f3_OrganizationandBasisofPresentationPolicies"/>
  <link:roleRef roleURI="http://www.wdc.com/role/OrganizationandBasisofPresentationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#OrganizationandBasisofPresentationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/OrganizationandBasisofPresentationDetails" xlink:type="extended" id="i4044d6f6689e43939147c13516b6a56c_OrganizationandBasisofPresentationDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RecentAccountingPronouncements" xlink:type="simple" xlink:href="wdc-20210402.xsd#RecentAccountingPronouncements"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RecentAccountingPronouncements" xlink:type="extended" id="i98ee762c029d4cd597ceff84c32f5b46_RecentAccountingPronouncements"/>
  <link:roleRef roleURI="http://www.wdc.com/role/Revenues" xlink:type="simple" xlink:href="wdc-20210402.xsd#Revenues"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/Revenues" xlink:type="extended" id="ia0f7dec34b464976bacdfb6f99db83c1_Revenues"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RevenuesTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#RevenuesTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RevenuesTables" xlink:type="extended" id="i71d0aa4698e148e799bc5e7600d027ae_RevenuesTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RevenuesRevenueRemainingPerformanceObligationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RevenuesRevenueRemainingPerformanceObligationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RevenuesRevenueRemainingPerformanceObligationDetails" xlink:type="extended" id="id4709919a764450f9cc43c412db21539_RevenuesRevenueRemainingPerformanceObligationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_cebdf524-e538-483a-88f6-cc83450ec5d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_cebdf524-e538-483a-88f6-cc83450ec5d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_91a8254a-01ef-4843-b91b-28f7a9fe5afe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_91a8254a-01ef-4843-b91b-28f7a9fe5afe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_3a70431e-f873-45a3-8716-9f9175a0e970" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_3a70431e-f873-45a3-8716-9f9175a0e970" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_ac1df07d-5bff-471d-abb3-3604826545e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_3a70431e-f873-45a3-8716-9f9175a0e970" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_ac1df07d-5bff-471d-abb3-3604826545e2" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RevenuesRevenueRemainingPerformanceObligationDetails_1" xlink:type="simple" xlink:href="wdc-20210402.xsd#RevenuesRevenueRemainingPerformanceObligationDetails_1"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RevenuesRevenueRemainingPerformanceObligationDetails_1" xlink:type="extended" id="i3588066585c5456a836c65af3326dd5d_RevenuesRevenueRemainingPerformanceObligationDetails_1">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_cebdf524-e538-483a-88f6-cc83450ec5d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_cebdf524-e538-483a-88f6-cc83450ec5d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_91a8254a-01ef-4843-b91b-28f7a9fe5afe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_91a8254a-01ef-4843-b91b-28f7a9fe5afe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_3a70431e-f873-45a3-8716-9f9175a0e970" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_aae828b7-4822-4369-b03f-b2773e8a458d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_3a70431e-f873-45a3-8716-9f9175a0e970" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RevenuesDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RevenuesDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RevenuesDisaggregationofRevenueDetails" xlink:type="extended" id="i13b1b74cce1849999251b6bcaf0f728a_RevenuesDisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_fc439723-648a-48fd-b3a5-910f5b1ae68b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_e192818a-514e-448b-a088-2fdd19a7dc9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_fc439723-648a-48fd-b3a5-910f5b1ae68b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_e192818a-514e-448b-a088-2fdd19a7dc9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_c01b49e3-c751-4e32-b62f-1b622984b4ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_fc439723-648a-48fd-b3a5-910f5b1ae68b" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_c01b49e3-c751-4e32-b62f-1b622984b4ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FormFactorAxis_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d" xlink:href="wdc-20210402.xsd#wdc_FormFactorAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c01b49e3-c751-4e32-b62f-1b622984b4ba" xlink:to="loc_wdc_FormFactorAxis_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FormFactorDomain_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d_default" xlink:href="wdc-20210402.xsd#wdc_FormFactorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_wdc_FormFactorAxis_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d" xlink:to="loc_wdc_FormFactorDomain_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FormFactorDomain_ed8cf403-77e9-4b26-a8b3-5502c57b7233" xlink:href="wdc-20210402.xsd#wdc_FormFactorDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_wdc_FormFactorAxis_7a210dd2-d3b0-4655-a807-9f6fe9ea4f0d" xlink:to="loc_wdc_FormFactorDomain_ed8cf403-77e9-4b26-a8b3-5502c57b7233" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_HDDMember_e65217b2-d318-427b-b357-9afeebf470a3" xlink:href="wdc-20210402.xsd#wdc_HDDMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wdc_FormFactorDomain_ed8cf403-77e9-4b26-a8b3-5502c57b7233" xlink:to="loc_wdc_HDDMember_e65217b2-d318-427b-b357-9afeebf470a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FlashbasedMember_950d21a1-3015-4387-8876-dc438c65ee28" xlink:href="wdc-20210402.xsd#wdc_FlashbasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wdc_FormFactorDomain_ed8cf403-77e9-4b26-a8b3-5502c57b7233" xlink:to="loc_wdc_FlashbasedMember_950d21a1-3015-4387-8876-dc438c65ee28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_7c860f12-0a14-4477-9c5e-f75c1bfb8b80" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c01b49e3-c751-4e32-b62f-1b622984b4ba" xlink:to="loc_srt_ProductOrServiceAxis_7c860f12-0a14-4477-9c5e-f75c1bfb8b80" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7c860f12-0a14-4477-9c5e-f75c1bfb8b80_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_7c860f12-0a14-4477-9c5e-f75c1bfb8b80" xlink:to="loc_srt_ProductsAndServicesDomain_7c860f12-0a14-4477-9c5e-f75c1bfb8b80_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f8b20e42-7e0d-46e0-bdcf-54fc4f04c148" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_7c860f12-0a14-4477-9c5e-f75c1bfb8b80" xlink:to="loc_srt_ProductsAndServicesDomain_f8b20e42-7e0d-46e0-bdcf-54fc4f04c148" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ClientDevicesMember_71efc2e3-679e-427d-a634-b56f4a63e587" xlink:href="wdc-20210402.xsd#wdc_ClientDevicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_f8b20e42-7e0d-46e0-bdcf-54fc4f04c148" xlink:to="loc_wdc_ClientDevicesMember_71efc2e3-679e-427d-a634-b56f4a63e587" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_DataCenterDevicesSolutionsMember_57821779-09d3-46bd-a8d6-aadd9e41f02b" xlink:href="wdc-20210402.xsd#wdc_DataCenterDevicesSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_f8b20e42-7e0d-46e0-bdcf-54fc4f04c148" xlink:to="loc_wdc_DataCenterDevicesSolutionsMember_57821779-09d3-46bd-a8d6-aadd9e41f02b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ClientSolutionsMember_419ef9af-0fd5-447f-9beb-9fe0d47d69d4" xlink:href="wdc-20210402.xsd#wdc_ClientSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_f8b20e42-7e0d-46e0-bdcf-54fc4f04c148" xlink:to="loc_wdc_ClientSolutionsMember_419ef9af-0fd5-447f-9beb-9fe0d47d69d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_69d1286a-5184-4f69-b3d7-03df456f98e6" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c01b49e3-c751-4e32-b62f-1b622984b4ba" xlink:to="loc_srt_StatementGeographicalAxis_69d1286a-5184-4f69-b3d7-03df456f98e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_69d1286a-5184-4f69-b3d7-03df456f98e6_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_69d1286a-5184-4f69-b3d7-03df456f98e6" xlink:to="loc_srt_SegmentGeographicalDomain_69d1286a-5184-4f69-b3d7-03df456f98e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_dab24501-08fe-4e6d-9d11-c59f257d6db1" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_69d1286a-5184-4f69-b3d7-03df456f98e6" xlink:to="loc_srt_SegmentGeographicalDomain_dab24501-08fe-4e6d-9d11-c59f257d6db1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_c292151b-fd4b-4c33-bf34-df12ff9ea01d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_dab24501-08fe-4e6d-9d11-c59f257d6db1" xlink:to="loc_srt_AmericasMember_c292151b-fd4b-4c33-bf34-df12ff9ea01d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EuropeMiddleEastAndAfricaMember_fd18e7c1-360f-41a0-a804-d5b2a97b78af" xlink:href="wdc-20210402.xsd#wdc_EuropeMiddleEastAndAfricaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_dab24501-08fe-4e6d-9d11-c59f257d6db1" xlink:to="loc_wdc_EuropeMiddleEastAndAfricaMember_fd18e7c1-360f-41a0-a804-d5b2a97b78af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaMember_09c0d68d-1238-45c7-af7b-705a094acd80" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_AsiaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_dab24501-08fe-4e6d-9d11-c59f257d6db1" xlink:to="loc_srt_AsiaMember_09c0d68d-1238-45c7-af7b-705a094acd80" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RevenuesAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RevenuesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RevenuesAdditionalInformationDetails" xlink:type="extended" id="i9361ec2337b24cc1b0ed1f5d449f4e1b_RevenuesAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_021c552a-05d3-4270-bfc8-0f70fecaab93" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_17b26cde-66b0-4e3c-b557-855a705886b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_021c552a-05d3-4270-bfc8-0f70fecaab93" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_17b26cde-66b0-4e3c-b557-855a705886b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_dd9b51d4-5d38-411a-bf6a-5d0e73024772" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_021c552a-05d3-4270-bfc8-0f70fecaab93" xlink:to="loc_us-gaap_ConcentrationRiskTable_dd9b51d4-5d38-411a-bf6a-5d0e73024772" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_dd9b51d4-5d38-411a-bf6a-5d0e73024772" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_d2bfb2ef-c669-46f0-904a-748ac3d1f694" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_4b55e0eb-c8aa-4c90-ad41-b01c0a6703a0" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_d2bfb2ef-c669-46f0-904a-748ac3d1f694" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_b79e7314-1f1e-4a7d-96cc-50d7e2d449ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_d2bfb2ef-c669-46f0-904a-748ac3d1f694" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_b79e7314-1f1e-4a7d-96cc-50d7e2d449ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_6a62182c-0468-41e3-9265-b85b3acba8a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_dd9b51d4-5d38-411a-bf6a-5d0e73024772" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_6a62182c-0468-41e3-9265-b85b3acba8a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_6a62182c-0468-41e3-9265-b85b3acba8a2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_6a62182c-0468-41e3-9265-b85b3acba8a2" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_6a62182c-0468-41e3-9265-b85b3acba8a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_e832d804-ecd2-4c37-8a66-4bd4540c621f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_6a62182c-0468-41e3-9265-b85b3acba8a2" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_e832d804-ecd2-4c37-8a66-4bd4540c621f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_b0ee49da-06bc-4b7d-97e2-7480e21a5370" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_e832d804-ecd2-4c37-8a66-4bd4540c621f" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_b0ee49da-06bc-4b7d-97e2-7480e21a5370" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_cbd000d2-fdb5-4cf4-9619-061534ea9971" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_dd9b51d4-5d38-411a-bf6a-5d0e73024772" xlink:to="loc_srt_MajorCustomersAxis_cbd000d2-fdb5-4cf4-9619-061534ea9971" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_cbd000d2-fdb5-4cf4-9619-061534ea9971_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_cbd000d2-fdb5-4cf4-9619-061534ea9971" xlink:to="loc_srt_NameOfMajorCustomerDomain_cbd000d2-fdb5-4cf4-9619-061534ea9971_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_d7b77d2c-d801-4ef6-84ef-9cea7e2fee43" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_cbd000d2-fdb5-4cf4-9619-061534ea9971" xlink:to="loc_srt_NameOfMajorCustomerDomain_d7b77d2c-d801-4ef6-84ef-9cea7e2fee43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TopTenCustomersMember_f9387069-00f8-40cd-9a09-4d3f041dae5a" xlink:href="wdc-20210402.xsd#wdc_TopTenCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_d7b77d2c-d801-4ef6-84ef-9cea7e2fee43" xlink:to="loc_wdc_TopTenCustomersMember_f9387069-00f8-40cd-9a09-4d3f041dae5a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementData" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementData"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementData" xlink:type="extended" id="idb89e1820bfc451b9b5df0df8d36fe68_SupplementalFinancialStatementData"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataTables" xlink:type="extended" id="i37d63f930fef48c4858dc3636397f1ed_SupplementalFinancialStatementDataTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataAdditionalInformationDetails" xlink:type="extended" id="i133e4b99f04c4e8bbcbe68375d7d2a18_SupplementalFinancialStatementDataAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c9bb5af3-397a-4afc-94f5-63b143a6cc21" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_31e9969e-79d3-4570-8d55-e6ff71c1b511" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleAndCollectionOfReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c9bb5af3-397a-4afc-94f5-63b143a6cc21" xlink:to="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_31e9969e-79d3-4570-8d55-e6ff71c1b511" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_716d9635-5eac-4b87-8686-7fb0226cabf4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c9bb5af3-397a-4afc-94f5-63b143a6cc21" xlink:to="loc_us-gaap_NotesReceivableNet_716d9635-5eac-4b87-8686-7fb0226cabf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_6e9fe4cc-2df1-40a5-97ca-2d9d54bff0e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c9bb5af3-397a-4afc-94f5-63b143a6cc21" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_6e9fe4cc-2df1-40a5-97ca-2d9d54bff0e1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_182e2880-e990-41a3-886f-e6aaa0ae5d78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_6e9fe4cc-2df1-40a5-97ca-2d9d54bff0e1" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_182e2880-e990-41a3-886f-e6aaa0ae5d78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_182e2880-e990-41a3-886f-e6aaa0ae5d78_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_182e2880-e990-41a3-886f-e6aaa0ae5d78" xlink:to="loc_us-gaap_ReceivableTypeDomain_182e2880-e990-41a3-886f-e6aaa0ae5d78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_8d5aa45b-a34b-452b-aebe-87783d605b1d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_182e2880-e990-41a3-886f-e6aaa0ae5d78" xlink:to="loc_us-gaap_ReceivableTypeDomain_8d5aa45b-a34b-452b-aebe-87783d605b1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FactoredReceivablesMember_f9458e24-c55f-4bfe-8ddf-419da6f275d4" xlink:href="wdc-20210402.xsd#wdc_FactoredReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_8d5aa45b-a34b-452b-aebe-87783d605b1d" xlink:to="loc_wdc_FactoredReceivablesMember_f9458e24-c55f-4bfe-8ddf-419da6f275d4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataInventoryDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataInventoryDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataInventoryDetails" xlink:type="extended" id="ia925d93f64504240a7d5bd21f0ad7f97_SupplementalFinancialStatementDataInventoryDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataPropertyPlantandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataPropertyPlantandEquipmentDetails" xlink:type="extended" id="i7bab79eab45c43b49da057ea6fb2392c_SupplementalFinancialStatementDataPropertyPlantandEquipmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_460e80ff-75b6-4e8a-bded-3ac8031f1aed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_d6144e06-74a5-445d-be2f-0d79cbe0b5ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_460e80ff-75b6-4e8a-bded-3ac8031f1aed" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_d6144e06-74a5-445d-be2f-0d79cbe0b5ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_6f53ad60-4980-463d-b2f5-26cf338ad67b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_d6144e06-74a5-445d-be2f-0d79cbe0b5ed" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_6f53ad60-4980-463d-b2f5-26cf338ad67b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_66e6accb-77af-4761-a96f-3d46cba9fab5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_d6144e06-74a5-445d-be2f-0d79cbe0b5ed" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_66e6accb-77af-4761-a96f-3d46cba9fab5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_5412b7bf-ad88-49e9-a6cb-d0d0601ed4e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_d6144e06-74a5-445d-be2f-0d79cbe0b5ed" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_5412b7bf-ad88-49e9-a6cb-d0d0601ed4e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b03e27b3-a22f-4c47-af1d-d59e723c286a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_460e80ff-75b6-4e8a-bded-3ac8031f1aed" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b03e27b3-a22f-4c47-af1d-d59e723c286a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7fe3c983-e322-4f7b-a3c2-68b22f4932dc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b03e27b3-a22f-4c47-af1d-d59e723c286a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7fe3c983-e322-4f7b-a3c2-68b22f4932dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7fe3c983-e322-4f7b-a3c2-68b22f4932dc_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7fe3c983-e322-4f7b-a3c2-68b22f4932dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7fe3c983-e322-4f7b-a3c2-68b22f4932dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7fe3c983-e322-4f7b-a3c2-68b22f4932dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_63b4b3f8-0390-480c-890e-205eb407ad40" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_us-gaap_LandMember_63b4b3f8-0390-480c-890e-205eb407ad40" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_2d286987-80e0-4110-a3a1-bf7f7cecd8fc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_2d286987-80e0-4110-a3a1-bf7f7cecd8fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_8fe8b3a7-304d-48c2-add3-8cc7b5f0a48b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_8fe8b3a7-304d-48c2-add3-8cc7b5f0a48b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ComputerEquipmentandSoftwareMember_aee19c11-9301-4cf7-983e-57f4f3719e9c" xlink:href="wdc-20210402.xsd#wdc_ComputerEquipmentandSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_wdc_ComputerEquipmentandSoftwareMember_aee19c11-9301-4cf7-983e-57f4f3719e9c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_470d24c4-7267-4bf0-86e9-4bc4c9975d09" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_470d24c4-7267-4bf0-86e9-4bc4c9975d09" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_c0841c65-e023-45f5-93cd-d46159efa861" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9db1d1d3-353a-40ed-8e5f-3736a00c3f28" xlink:to="loc_us-gaap_ConstructionInProgressMember_c0841c65-e023-45f5-93cd-d46159efa861" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataGoodwillRollForwardDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataGoodwillRollForwardDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataGoodwillRollForwardDetails" xlink:type="extended" id="ife275c65fd6048c4949da15c111e8ff5_SupplementalFinancialStatementDataGoodwillRollForwardDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataIntangibleAssetsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataIntangibleAssetsDetails" xlink:type="extended" id="idf2a467589234b709b7547c4fec2b7df_SupplementalFinancialStatementDataIntangibleAssetsDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataWarrantyAccrualRollForwardDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataWarrantyAccrualRollForwardDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataWarrantyAccrualRollForwardDetails" xlink:type="extended" id="ia197b186df44493098178949e71b77e5_SupplementalFinancialStatementDataWarrantyAccrualRollForwardDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataTotalWarrantyAccrualDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataTotalWarrantyAccrualDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataTotalWarrantyAccrualDetails" xlink:type="extended" id="id5b034ab7433440089ec19a98a6116bf_SupplementalFinancialStatementDataTotalWarrantyAccrualDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataOtherLiabilitiesDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataOtherLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataOtherLiabilitiesDetails" xlink:type="extended" id="i9a75a80e26054d8fa3d1427516d05a86_SupplementalFinancialStatementDataOtherLiabilitiesDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/SupplementalFinancialStatementDataAccumulatedOtherComprehensiveIncomeRollForwardDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#SupplementalFinancialStatementDataAccumulatedOtherComprehensiveIncomeRollForwardDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/SupplementalFinancialStatementDataAccumulatedOtherComprehensiveIncomeRollForwardDetails" xlink:type="extended" id="if9182d76710e486687eb86b2852d89e7_SupplementalFinancialStatementDataAccumulatedOtherComprehensiveIncomeRollForwardDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4f25f5c6-690d-43d5-9425-1f4313e9da95" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4f25f5c6-690d-43d5-9425-1f4313e9da95" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_155d7121-757f-4fef-8766-92b9cfd0a415" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:to="loc_us-gaap_StockholdersEquity_155d7121-757f-4fef-8766-92b9cfd0a415" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_ffb805cc-7a1a-4d90-ae3e-142f7ae907c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:to="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_ffb805cc-7a1a-4d90-ae3e-142f7ae907c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_659eae7e-eb1c-4805-9c8c-7df770a61fcb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_659eae7e-eb1c-4805-9c8c-7df770a61fcb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_fc23a68c-84af-4ef7-8868-20e60a1f4ec1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_fc23a68c-84af-4ef7-8868-20e60a1f4ec1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e14e9207-c1a7-4a86-af82-1ffd78eb45c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_a33b30c1-3a05-4c6a-840b-3683657a0f0a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e14e9207-c1a7-4a86-af82-1ffd78eb45c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_023f2107-e2d9-4b12-9a22-cb3c4b44d9ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_2e7e9899-54d5-4cb5-a2a5-c5cb01f643e6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4f25f5c6-690d-43d5-9425-1f4313e9da95" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_2e7e9899-54d5-4cb5-a2a5-c5cb01f643e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_cf8c7ceb-ba43-4dbc-b1f3-f250612e3efd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4f25f5c6-690d-43d5-9425-1f4313e9da95" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_cf8c7ceb-ba43-4dbc-b1f3-f250612e3efd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_59942ef2-22eb-43a5-8dd7-1bdfd14f08a3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4f25f5c6-690d-43d5-9425-1f4313e9da95" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_59942ef2-22eb-43a5-8dd7-1bdfd14f08a3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_39621022-fcbf-49d6-98e6-fe940f188746" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_59942ef2-22eb-43a5-8dd7-1bdfd14f08a3" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_39621022-fcbf-49d6-98e6-fe940f188746" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_39621022-fcbf-49d6-98e6-fe940f188746_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_39621022-fcbf-49d6-98e6-fe940f188746" xlink:to="loc_us-gaap_EquityComponentDomain_39621022-fcbf-49d6-98e6-fe940f188746_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_39621022-fcbf-49d6-98e6-fe940f188746" xlink:to="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_1791e792-85d9-4e86-8b9e-b4ad79adff98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_1791e792-85d9-4e86-8b9e-b4ad79adff98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_88fedbe3-cb59-4a50-af19-31d13b413efb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_88fedbe3-cb59-4a50-af19-31d13b413efb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_32e3ec04-5fe5-4137-905f-3f0a8bbf9f43" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_32e3ec04-5fe5-4137-905f-3f0a8bbf9f43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_d81875ab-aeb3-4694-b0f9-4870b0005d3c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b3530285-6d47-4296-a4ac-e10e3f09e598" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_d81875ab-aeb3-4694-b0f9-4870b0005d3c" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/FairValueMeasurementsandInvestments" xlink:type="simple" xlink:href="wdc-20210402.xsd#FairValueMeasurementsandInvestments"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/FairValueMeasurementsandInvestments" xlink:type="extended" id="ib1bec7e7644841af847c8d792ba2fa8f_FairValueMeasurementsandInvestments"/>
  <link:roleRef roleURI="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#FairValueMeasurementsandInvestmentsTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsTables" xlink:type="extended" id="id76ab3d74cb64f6cb52e5268284bb13e_FairValueMeasurementsandInvestmentsTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetail" xlink:type="simple" xlink:href="wdc-20210402.xsd#FairValueMeasurementsandInvestmentsFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetail"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetail" xlink:type="extended" id="icf7153fb79f84397b2bdddae8924aa7c_FairValueMeasurementsandInvestmentsFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetail">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_3c663e57-9026-487d-8aae-f35fa7e94ec7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_6215d6f0-c3a6-47ec-ac34-ffc47e173f8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_3c663e57-9026-487d-8aae-f35fa7e94ec7" xlink:to="loc_us-gaap_AssetsAbstract_6215d6f0-c3a6-47ec-ac34-ffc47e173f8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_5020a84a-fcb4-4300-aaf4-b6163cde725f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_6215d6f0-c3a6-47ec-ac34-ffc47e173f8b" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_5020a84a-fcb4-4300-aaf4-b6163cde725f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_7d563075-9474-4767-86d9-3bb9b17cffa1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_6215d6f0-c3a6-47ec-ac34-ffc47e173f8b" xlink:to="loc_us-gaap_DerivativeAssets_7d563075-9474-4767-86d9-3bb9b17cffa1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_c8f6a0eb-d0c6-4867-aa2c-aaa59086cc55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_6215d6f0-c3a6-47ec-ac34-ffc47e173f8b" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_c8f6a0eb-d0c6-4867-aa2c-aaa59086cc55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_0a083a79-046c-4027-88a5-dbd569ce425d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_3c663e57-9026-487d-8aae-f35fa7e94ec7" xlink:to="loc_us-gaap_LiabilitiesAbstract_0a083a79-046c-4027-88a5-dbd569ce425d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_d393b3dc-9a61-4500-ae49-e703a2230266" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_0a083a79-046c-4027-88a5-dbd569ce425d" xlink:to="loc_us-gaap_DerivativeLiabilities_d393b3dc-9a61-4500-ae49-e703a2230266" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_bd1ab456-8ef0-46f0-9138-4be10f38ccd6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_0a083a79-046c-4027-88a5-dbd569ce425d" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_bd1ab456-8ef0-46f0-9138-4be10f38ccd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9c8edcf3-5d90-4e01-95ea-613a7261db02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_3c663e57-9026-487d-8aae-f35fa7e94ec7" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9c8edcf3-5d90-4e01-95ea-613a7261db02" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_3ee12e6b-9478-4c1f-bac1-0353059f4d8f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9c8edcf3-5d90-4e01-95ea-613a7261db02" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_3ee12e6b-9478-4c1f-bac1-0353059f4d8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_3ee12e6b-9478-4c1f-bac1-0353059f4d8f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_3ee12e6b-9478-4c1f-bac1-0353059f4d8f" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_3ee12e6b-9478-4c1f-bac1-0353059f4d8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_a4d16990-c84e-43fb-9d29-b8ebe7cb1c62" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_3ee12e6b-9478-4c1f-bac1-0353059f4d8f" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_a4d16990-c84e-43fb-9d29-b8ebe7cb1c62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_e1a88e14-8b6a-407f-8d25-a0f14268bd73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_a4d16990-c84e-43fb-9d29-b8ebe7cb1c62" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_e1a88e14-8b6a-407f-8d25-a0f14268bd73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e52b9054-d204-43f0-aaa8-612f36902cf2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9c8edcf3-5d90-4e01-95ea-613a7261db02" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e52b9054-d204-43f0-aaa8-612f36902cf2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e52b9054-d204-43f0-aaa8-612f36902cf2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e52b9054-d204-43f0-aaa8-612f36902cf2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e52b9054-d204-43f0-aaa8-612f36902cf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dec454ab-6250-414c-921f-d25396b89b1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e52b9054-d204-43f0-aaa8-612f36902cf2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dec454ab-6250-414c-921f-d25396b89b1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_a9e00c6a-508b-4774-b61c-99da721212c4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dec454ab-6250-414c-921f-d25396b89b1e" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_a9e00c6a-508b-4774-b61c-99da721212c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_78718b48-70a5-429d-b729-c6576b708ed5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dec454ab-6250-414c-921f-d25396b89b1e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_78718b48-70a5-429d-b729-c6576b708ed5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_e595c3bf-2bb3-42c0-b9c1-7198da89d3f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dec454ab-6250-414c-921f-d25396b89b1e" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_e595c3bf-2bb3-42c0-b9c1-7198da89d3f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_55c16392-723c-4bed-a637-c46c127d2e05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_9c8edcf3-5d90-4e01-95ea-613a7261db02" xlink:to="loc_us-gaap_FinancialInstrumentAxis_55c16392-723c-4bed-a637-c46c127d2e05" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_55c16392-723c-4bed-a637-c46c127d2e05_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_55c16392-723c-4bed-a637-c46c127d2e05" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_55c16392-723c-4bed-a637-c46c127d2e05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f9f10dd-521d-4a71-846e-719060506417" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_55c16392-723c-4bed-a637-c46c127d2e05" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f9f10dd-521d-4a71-846e-719060506417" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_48dc979b-582d-4a98-81ce-aaa5c27e4b67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f9f10dd-521d-4a71-846e-719060506417" xlink:to="loc_us-gaap_MoneyMarketFundsMember_48dc979b-582d-4a98-81ce-aaa5c27e4b67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_67a45248-29ed-46df-94e9-59f02d437c5f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f9f10dd-521d-4a71-846e-719060506417" xlink:to="loc_us-gaap_ForeignExchangeContractMember_67a45248-29ed-46df-94e9-59f02d437c5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_5f9ffa42-ead1-427b-a558-a5efb47dad5b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3f9f10dd-521d-4a71-846e-719060506417" xlink:to="loc_us-gaap_InterestRateSwapMember_5f9ffa42-ead1-427b-a558-a5efb47dad5b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsDebtInstrumentFairValueDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#FairValueMeasurementsandInvestmentsDebtInstrumentFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/FairValueMeasurementsandInvestmentsDebtInstrumentFairValueDetails" xlink:type="extended" id="iaf27d47afd454f57a44cae7ffe32e02e_FairValueMeasurementsandInvestmentsDebtInstrumentFairValueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_d59bb730-094b-4a46-b39a-237a5125ec10" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_0a155817-2dd5-4061-9d73-f960c3c36bc2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d59bb730-094b-4a46-b39a-237a5125ec10" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_0a155817-2dd5-4061-9d73-f960c3c36bc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_ab23d880-d7f0-4ca6-8d90-81824d2d63cd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d59bb730-094b-4a46-b39a-237a5125ec10" xlink:to="loc_us-gaap_LongTermDebtFairValue_ab23d880-d7f0-4ca6-8d90-81824d2d63cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d59bb730-094b-4a46-b39a-237a5125ec10" xlink:to="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_949e10d5-f6a9-4316-a126-6ba599be5394" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e56b9755-5ad1-4cf2-9e7e-f581ddd5045e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_949e10d5-f6a9-4316-a126-6ba599be5394" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_61f8a78b-5a9d-4925-947f-d66b0f198844" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_949e10d5-f6a9-4316-a126-6ba599be5394" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_61f8a78b-5a9d-4925-947f-d66b0f198844" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_ee6302d6-4459-47e7-aed4-6111f0d1a74a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_ee6302d6-4459-47e7-aed4-6111f0d1a74a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ee6302d6-4459-47e7-aed4-6111f0d1a74a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_ee6302d6-4459-47e7-aed4-6111f0d1a74a" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_ee6302d6-4459-47e7-aed4-6111f0d1a74a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8fd33e9d-fe8e-4871-8e3f-5c6fe661568b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_ee6302d6-4459-47e7-aed4-6111f0d1a74a" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8fd33e9d-fe8e-4871-8e3f-5c6fe661568b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7aeb85db-7af0-4a82-aacf-430c021fd3e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8fd33e9d-fe8e-4871-8e3f-5c6fe661568b" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7aeb85db-7af0-4a82-aacf-430c021fd3e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_644bf88b-8d23-4d6c-a255-202c11d3fd32" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7aeb85db-7af0-4a82-aacf-430c021fd3e1" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_644bf88b-8d23-4d6c-a255-202c11d3fd32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_fe8977fa-2037-4177-97dc-4961f2663d44" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7aeb85db-7af0-4a82-aacf-430c021fd3e1" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_fe8977fa-2037-4177-97dc-4961f2663d44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_73cee774-72f7-42d1-8b04-4ac0977e39f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:to="loc_us-gaap_DebtInstrumentAxis_73cee774-72f7-42d1-8b04-4ac0977e39f7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_73cee774-72f7-42d1-8b04-4ac0977e39f7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_73cee774-72f7-42d1-8b04-4ac0977e39f7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_73cee774-72f7-42d1-8b04-4ac0977e39f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_73cee774-72f7-42d1-8b04-4ac0977e39f7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_7a0a554a-0112-4215-84e1-9338f780f176" xlink:href="wdc-20210402.xsd#wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:to="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_7a0a554a-0112-4215-84e1-9338f780f176" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TermLoanA1Member_45c687ad-a6e0-47f7-a0aa-8ea6edb3847c" xlink:href="wdc-20210402.xsd#wdc_TermLoanA1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:to="loc_wdc_TermLoanA1Member_45c687ad-a6e0-47f7-a0aa-8ea6edb3847c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_U.S.TermLoanB4Member_e8f07146-f885-46de-b62b-4c7481ccd672" xlink:href="wdc-20210402.xsd#wdc_U.S.TermLoanB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:to="loc_wdc_U.S.TermLoanB4Member_e8f07146-f885-46de-b62b-4c7481ccd672" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember_c1861192-9200-44dc-bde2-28b37044667c" xlink:href="wdc-20210402.xsd#wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:to="loc_wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember_c1861192-9200-44dc-bde2-28b37044667c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember_1077768c-ea9e-4470-99aa-a963a3a50ba3" xlink:href="wdc-20210402.xsd#wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_948b7422-d81d-4640-a6eb-1757111db0bc" xlink:to="loc_wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember_1077768c-ea9e-4470-99aa-a963a3a50ba3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_724af4b6-5b80-4a86-8a63-52f563c7e18f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a6cfd7aa-6ea1-44f8-8874-ed474240c045" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_724af4b6-5b80-4a86-8a63-52f563c7e18f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_724af4b6-5b80-4a86-8a63-52f563c7e18f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_724af4b6-5b80-4a86-8a63-52f563c7e18f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_724af4b6-5b80-4a86-8a63-52f563c7e18f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e9102455-b1ff-489c-a193-107ca867ac47" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_724af4b6-5b80-4a86-8a63-52f563c7e18f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e9102455-b1ff-489c-a193-107ca867ac47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_6c130e4e-0e67-40b5-92b8-9ec25bf90fb9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e9102455-b1ff-489c-a193-107ca867ac47" xlink:to="loc_us-gaap_ConvertibleDebtMember_6c130e4e-0e67-40b5-92b8-9ec25bf90fb9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/DerivativesInstrumentsandHedgingActivities" xlink:type="simple" xlink:href="wdc-20210402.xsd#DerivativesInstrumentsandHedgingActivities"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/DerivativesInstrumentsandHedgingActivities" xlink:type="extended" id="i4f7acc80c26942d78f517fb1ddcc6a2b_DerivativesInstrumentsandHedgingActivities"/>
  <link:roleRef roleURI="http://www.wdc.com/role/DerivativesInstrumentsandHedgingActivitiesDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#DerivativesInstrumentsandHedgingActivitiesDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/DerivativesInstrumentsandHedgingActivitiesDetails" xlink:type="extended" id="i5723f1444a03424f9823ace87debdb38_DerivativesInstrumentsandHedgingActivitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_0ce8597d-1b58-46fa-b739-662986537a11" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTermOfContract_b6a909d7-408b-4d7c-b255-c88a280291d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0ce8597d-1b58-46fa-b739-662986537a11" xlink:to="loc_us-gaap_DerivativeTermOfContract_b6a909d7-408b-4d7c-b255-c88a280291d9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months_958c0c71-4348-468c-b1ba-1c540bdf2570" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0ce8597d-1b58-46fa-b739-662986537a11" xlink:to="loc_us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months_958c0c71-4348-468c-b1ba-1c540bdf2570" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_3e77fd23-c374-4468-94c5-f81a790a37d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0ce8597d-1b58-46fa-b739-662986537a11" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_3e77fd23-c374-4468-94c5-f81a790a37d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_22fb28da-7d10-4d90-bb2c-121dede0ca07" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_3e77fd23-c374-4468-94c5-f81a790a37d5" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_22fb28da-7d10-4d90-bb2c-121dede0ca07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_22fb28da-7d10-4d90-bb2c-121dede0ca07_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_22fb28da-7d10-4d90-bb2c-121dede0ca07" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_22fb28da-7d10-4d90-bb2c-121dede0ca07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_2eb982a8-af56-4fac-bf8c-272c6a7d6d96" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_22fb28da-7d10-4d90-bb2c-121dede0ca07" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_2eb982a8-af56-4fac-bf8c-272c6a7d6d96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ForeignExchangeForwardContractsDesignatedMember_66935ae3-759b-44ff-9115-97213ab8eb2f" xlink:href="wdc-20210402.xsd#wdc_ForeignExchangeForwardContractsDesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2eb982a8-af56-4fac-bf8c-272c6a7d6d96" xlink:to="loc_wdc_ForeignExchangeForwardContractsDesignatedMember_66935ae3-759b-44ff-9115-97213ab8eb2f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/Debt" xlink:type="simple" xlink:href="wdc-20210402.xsd#Debt"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/Debt" xlink:type="extended" id="i0427dabd268a4aa49ffcaeb9cc9e86c7_Debt"/>
  <link:roleRef roleURI="http://www.wdc.com/role/DebtTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#DebtTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/DebtTables" xlink:type="extended" id="ied70025d334748debad66f91274f9ab5_DebtTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/DebtScheduleofDebtDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#DebtScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/DebtScheduleofDebtDetails" xlink:type="extended" id="idc00c185dc3444aeb0143b506c90e891_DebtScheduleofDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_be2c825e-bd5d-4134-b87a-c6e507c8590a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_be2c825e-bd5d-4134-b87a-c6e507c8590a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_fc23ed7c-edde-4f18-90f6-afd1e40cb9af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_fc23ed7c-edde-4f18-90f6-afd1e40cb9af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_e197c5c1-7c01-4933-83a7-fdc6e96a912a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_e197c5c1-7c01-4933-83a7-fdc6e96a912a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_9e1c4741-0ef9-4af2-a22d-abc03625aa96" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_LongTermDebt_9e1c4741-0ef9-4af2-a22d-abc03625aa96" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_5e777029-eb99-4632-aa4c-caef3320722c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_LongTermDebtCurrent_5e777029-eb99-4632-aa4c-caef3320722c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_e838c788-72aa-4f3b-8eae-675074d61cf5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_e838c788-72aa-4f3b-8eae-675074d61cf5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_0450c9fe-1262-4d56-9223-91f44a301c45" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49469d50-f327-4d9d-833e-c95158678265" xlink:to="loc_us-gaap_DebtInstrumentTable_0450c9fe-1262-4d56-9223-91f44a301c45" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_9d5f02cb-58b1-4709-94a3-38bdeb391e78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0450c9fe-1262-4d56-9223-91f44a301c45" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_9d5f02cb-58b1-4709-94a3-38bdeb391e78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_9d5f02cb-58b1-4709-94a3-38bdeb391e78_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9d5f02cb-58b1-4709-94a3-38bdeb391e78" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_9d5f02cb-58b1-4709-94a3-38bdeb391e78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0c1ed208-9596-43f0-bceb-be5a3e9ede54" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9d5f02cb-58b1-4709-94a3-38bdeb391e78" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0c1ed208-9596-43f0-bceb-be5a3e9ede54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_2532c1c8-9e83-4c87-8038-abe821224795" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_0c1ed208-9596-43f0-bceb-be5a3e9ede54" xlink:to="loc_us-gaap_ConvertibleDebtMember_2532c1c8-9e83-4c87-8038-abe821224795" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_1fc5f4c7-b341-4d7f-8507-c0283f6b8171" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0450c9fe-1262-4d56-9223-91f44a301c45" xlink:to="loc_us-gaap_DebtInstrumentAxis_1fc5f4c7-b341-4d7f-8507-c0283f6b8171" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1fc5f4c7-b341-4d7f-8507-c0283f6b8171_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1fc5f4c7-b341-4d7f-8507-c0283f6b8171" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1fc5f4c7-b341-4d7f-8507-c0283f6b8171_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1fc5f4c7-b341-4d7f-8507-c0283f6b8171" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_0124dc0f-8775-4220-b4f2-620ffd993a13" xlink:href="wdc-20210402.xsd#wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:to="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_0124dc0f-8775-4220-b4f2-620ffd993a13" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TermLoanA1Member_49813d39-5eec-4bfc-add6-3d8d52ba599a" xlink:href="wdc-20210402.xsd#wdc_TermLoanA1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:to="loc_wdc_TermLoanA1Member_49813d39-5eec-4bfc-add6-3d8d52ba599a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_U.S.TermLoanB4Member_c25d5740-acc1-428c-aad5-3c7debd30665" xlink:href="wdc-20210402.xsd#wdc_U.S.TermLoanB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:to="loc_wdc_U.S.TermLoanB4Member_c25d5740-acc1-428c-aad5-3c7debd30665" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember_05a41798-d91a-408b-8efc-0df1b25a1b5d" xlink:href="wdc-20210402.xsd#wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:to="loc_wdc_OnePointFiftyPercentSeniorConvertibleNotesDueTwoThousandTwentyFourMember_05a41798-d91a-408b-8efc-0df1b25a1b5d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember_4b8ab7bc-4c21-4510-9274-1adccba18078" xlink:href="wdc-20210402.xsd#wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f2f2def1-9450-4067-b0de-b32ae52f263d" xlink:to="loc_wdc_FourPointSeventyFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySixMember_4b8ab7bc-4c21-4510-9274-1adccba18078" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/DebtAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#DebtAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/DebtAdditionalInformationDetails" xlink:type="extended" id="id1bdcab8077347479cf270cf2e550c62_DebtAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_eec7727f-7044-407e-a484-8f7e91454773" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_f95b9218-58c6-44d3-88d8-b223e2ad7049" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_eec7727f-7044-407e-a484-8f7e91454773" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_f95b9218-58c6-44d3-88d8-b223e2ad7049" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_94687461-93a1-4cf0-83ad-28ae47918518" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_eec7727f-7044-407e-a484-8f7e91454773" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_94687461-93a1-4cf0-83ad-28ae47918518" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_da2f3a3e-0b06-4882-81b5-cbae6ea7fbf1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_eec7727f-7044-407e-a484-8f7e91454773" xlink:to="loc_us-gaap_DebtInstrumentTable_da2f3a3e-0b06-4882-81b5-cbae6ea7fbf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6c7d3df6-225f-438c-800a-ff6743bdbaf4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_da2f3a3e-0b06-4882-81b5-cbae6ea7fbf1" xlink:to="loc_us-gaap_DebtInstrumentAxis_6c7d3df6-225f-438c-800a-ff6743bdbaf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6c7d3df6-225f-438c-800a-ff6743bdbaf4_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6c7d3df6-225f-438c-800a-ff6743bdbaf4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6c7d3df6-225f-438c-800a-ff6743bdbaf4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6dd34971-2259-4a6c-a4a8-e87ed56f9452" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6c7d3df6-225f-438c-800a-ff6743bdbaf4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6dd34971-2259-4a6c-a4a8-e87ed56f9452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_U.S.TermLoanB4Member_997fffd6-e51c-4853-8e00-34672ef57406" xlink:href="wdc-20210402.xsd#wdc_U.S.TermLoanB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6dd34971-2259-4a6c-a4a8-e87ed56f9452" xlink:to="loc_wdc_U.S.TermLoanB4Member_997fffd6-e51c-4853-8e00-34672ef57406" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_d9e6c7ad-aed0-4634-8cc1-d6cdaf569fb8" xlink:href="wdc-20210402.xsd#wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6dd34971-2259-4a6c-a4a8-e87ed56f9452" xlink:to="loc_wdc_ConvertibleSeniorNotesDueTwoThousandTwentyMemberMember_d9e6c7ad-aed0-4634-8cc1-d6cdaf569fb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_74c53b69-3c70-470e-be97-609136856d5c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_da2f3a3e-0b06-4882-81b5-cbae6ea7fbf1" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_74c53b69-3c70-470e-be97-609136856d5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_74c53b69-3c70-470e-be97-609136856d5c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_74c53b69-3c70-470e-be97-609136856d5c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_74c53b69-3c70-470e-be97-609136856d5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_0935527b-e392-444b-aae0-4845c3e97b0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_74c53b69-3c70-470e-be97-609136856d5c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_0935527b-e392-444b-aae0-4845c3e97b0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_a6bf78fe-d01f-4320-aacf-5e2fa57604f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_0935527b-e392-444b-aae0-4845c3e97b0c" xlink:to="loc_us-gaap_SubsequentEventMember_a6bf78fe-d01f-4320-aacf-5e2fa57604f9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlans" xlink:type="simple" xlink:href="wdc-20210402.xsd#PensionsandOtherPostRetirementBenefitPlans"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlans" xlink:type="extended" id="i5f02b066b4d84d8c8c943091131dcd8e_PensionsandOtherPostRetirementBenefitPlans"/>
  <link:roleRef roleURI="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#PensionsandOtherPostRetirementBenefitPlansTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansTables" xlink:type="extended" id="i413384f06bb04cb294c33cb260e37d58_PensionsandOtherPostRetirementBenefitPlansTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#PensionsandOtherPostRetirementBenefitPlansAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansAdditionalInformationDetails" xlink:type="extended" id="i1ea7017143624175b19e9cf2baecd70a_PensionsandOtherPostRetirementBenefitPlansAdditionalInformationDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansObligationsandFundedStatusDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#PensionsandOtherPostRetirementBenefitPlansObligationsandFundedStatusDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansObligationsandFundedStatusDetails" xlink:type="extended" id="i34e2f69d05bb4365bef23c34eb7445b3_PensionsandOtherPostRetirementBenefitPlansObligationsandFundedStatusDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansUnfundedAmountsRecognizedonConsolidatedBalanceSheetsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#PensionsandOtherPostRetirementBenefitPlansUnfundedAmountsRecognizedonConsolidatedBalanceSheetsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/PensionsandOtherPostRetirementBenefitPlansUnfundedAmountsRecognizedonConsolidatedBalanceSheetsDetails" xlink:type="extended" id="idfa5df75daaf4073b529f97f6606c535_PensionsandOtherPostRetirementBenefitPlansUnfundedAmountsRecognizedonConsolidatedBalanceSheetsDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingencies" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingencies"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingencies" xlink:type="extended" id="i636ea3b86e374e699f3f4e8e5f78ea73_RelatedPartiesandRelatedCommitmentsandContingencies"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesTables" xlink:type="extended" id="i98de9bfe0198484a92dfd83e992db7bf_RelatedPartiesandRelatedCommitmentsandContingenciesTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesEquityInvestmentsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesEquityInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesEquityInvestmentsDetails" xlink:type="extended" id="i12e00fba76e54ec6bed716f273a471e6_RelatedPartiesandRelatedCommitmentsandContingenciesEquityInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_9e3924c1-6f4a-4866-aab1-2382f55b5fd9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableRelatedParties_59c44a22-130f-4923-8133-6dcd3d1cbb0e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_9e3924c1-6f4a-4866-aab1-2382f55b5fd9" xlink:to="loc_us-gaap_NotesReceivableRelatedParties_59c44a22-130f-4923-8133-6dcd3d1cbb0e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Investments_e415e201-8d38-450e-95ce-1bcafbeda337" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Investments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_9e3924c1-6f4a-4866-aab1-2382f55b5fd9" xlink:to="loc_us-gaap_Investments_e415e201-8d38-450e-95ce-1bcafbeda337" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_NotesReceivableAndInvestmentsInRelatedParties_66641fb4-c4e2-41fc-9991-12562da1bd23" xlink:href="wdc-20210402.xsd#wdc_NotesReceivableAndInvestmentsInRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_9e3924c1-6f4a-4866-aab1-2382f55b5fd9" xlink:to="loc_wdc_NotesReceivableAndInvestmentsInRelatedParties_66641fb4-c4e2-41fc-9991-12562da1bd23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_58f4eb84-6dc3-4759-a180-4218d59fbbc7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_9e3924c1-6f4a-4866-aab1-2382f55b5fd9" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_58f4eb84-6dc3-4759-a180-4218d59fbbc7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_58f4eb84-6dc3-4759-a180-4218d59fbbc7" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_f0b5947d-bb8b-4fb4-9be4-9a339ebd9887" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FlashPartnersLtdMember_a7b4616b-3331-4134-bf91-d9e78e022b99" xlink:href="wdc-20210402.xsd#wdc_FlashPartnersLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:to="loc_wdc_FlashPartnersLtdMember_a7b4616b-3331-4134-bf91-d9e78e022b99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FlashAllianceLtdMember_a2bbeb3d-537e-4338-9f4c-dcd0c0a6f3c4" xlink:href="wdc-20210402.xsd#wdc_FlashAllianceLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:to="loc_wdc_FlashAllianceLtdMember_a2bbeb3d-537e-4338-9f4c-dcd0c0a6f3c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FlashForwardLtdMember_2503e7a8-6305-4228-a3a5-9b6d5453c286" xlink:href="wdc-20210402.xsd#wdc_FlashForwardLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:to="loc_wdc_FlashForwardLtdMember_2503e7a8-6305-4228-a3a5-9b6d5453c286" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_81e3e482-1cd3-4899-b8ce-8e20b31f5bd5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_5f8a3614-7298-40ff-bf95-edf5de23f498" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_81e3e482-1cd3-4899-b8ce-8e20b31f5bd5" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails" xlink:type="extended" id="i8cfd738af9e14cc6ad0bf7eeec55c37e_RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_NumberOfLegalEntities_d0f2237d-74b1-4305-8a13-bf9a455e47fb" xlink:href="wdc-20210402.xsd#wdc_NumberOfLegalEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_NumberOfLegalEntities_d0f2237d-74b1-4305-8a13-bf9a455e47fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_0e74434c-691f-4fa1-af7d-fccfae40a43a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_0e74434c-691f-4fa1-af7d-fccfae40a43a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_dfdf70be-e6bc-4082-bbfa-127fff57183b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_dfdf70be-e6bc-4082-bbfa-127fff57183b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_InvestmentFundingCommitments_0ad04ca0-c5d6-4068-8b02-6601bce81a5a" xlink:href="wdc-20210402.xsd#wdc_InvestmentFundingCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_InvestmentFundingCommitments_0ad04ca0-c5d6-4068-8b02-6601bce81a5a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_LossOnBusinessInterruption_8f3b0632-8757-4ebe-bb09-1ce942c70907" xlink:href="wdc-20210402.xsd#wdc_LossOnBusinessInterruption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_LossOnBusinessInterruption_8f3b0632-8757-4ebe-bb09-1ce942c70907" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainOnBusinessInterruptionInsuranceRecovery_004f876e-afe2-48a5-9bb1-e1c9af6a1a55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainOnBusinessInterruptionInsuranceRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_GainOnBusinessInterruptionInsuranceRecovery_004f876e-afe2-48a5-9bb1-e1c9af6a1a55" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_406032e3-1ea6-4fae-ab15-9682b94bad34" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_OtherCommitment_406032e3-1ea6-4fae-ab15-9682b94bad34" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OtherCommitmentPeriod_13b5d47b-b2c9-4a17-9e2a-ab73dae8d7d3" xlink:href="wdc-20210402.xsd#wdc_OtherCommitmentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_OtherCommitmentPeriod_13b5d47b-b2c9-4a17-9e2a-ab73dae8d7d3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OtherCommitmentRemainingCommittedPrepayments_759e1bf2-a124-4cbf-a2bd-694039b82d84" xlink:href="wdc-20210402.xsd#wdc_OtherCommitmentRemainingCommittedPrepayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_OtherCommitmentRemainingCommittedPrepayments_759e1bf2-a124-4cbf-a2bd-694039b82d84" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_89e58bd1-8d3d-43ba-a3a4-baa948f92704" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_89e58bd1-8d3d-43ba-a3a4-baa948f92704" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_PartnersOwnershipInVentureBusiness_2dc75f91-4cab-4991-85a3-c0770f53fb8c" xlink:href="wdc-20210402.xsd#wdc_PartnersOwnershipInVentureBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_wdc_PartnersOwnershipInVentureBusiness_2dc75f91-4cab-4991-85a3-c0770f53fb8c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_a3c0bee4-b4c0-48b4-8f83-b0b7b7d372c5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_a3c0bee4-b4c0-48b4-8f83-b0b7b7d372c5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_76653d9a-ea47-46ae-be33-93b10166faa3" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_25b82595-0f09-43fa-b9f3-2fb567985528" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_25b82595-0f09-43fa-b9f3-2fb567985528" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_25b82595-0f09-43fa-b9f3-2fb567985528_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_25b82595-0f09-43fa-b9f3-2fb567985528" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_25b82595-0f09-43fa-b9f3-2fb567985528_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_688e56c3-a77d-4e26-8ace-6b25b747e158" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_25b82595-0f09-43fa-b9f3-2fb567985528" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_688e56c3-a77d-4e26-8ace-6b25b747e158" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_220a16e0-f982-4d99-9aca-3a34578bb27d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_688e56c3-a77d-4e26-8ace-6b25b747e158" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_220a16e0-f982-4d99-9aca-3a34578bb27d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_aa2f8a49-bd10-45aa-baf5-2fe78813a805" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_688e56c3-a77d-4e26-8ace-6b25b747e158" xlink:to="loc_us-gaap_AccountsReceivableMember_aa2f8a49-bd10-45aa-baf5-2fe78813a805" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_50f80b0d-1de9-4ae4-b194-3398474315a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_us-gaap_OtherCommitmentsAxis_50f80b0d-1de9-4ae4-b194-3398474315a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_50f80b0d-1de9-4ae4-b194-3398474315a2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_50f80b0d-1de9-4ae4-b194-3398474315a2" xlink:to="loc_us-gaap_OtherCommitmentsDomain_50f80b0d-1de9-4ae4-b194-3398474315a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_6dbb830e-fa26-4ccf-9a95-fa25bb954833" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_50f80b0d-1de9-4ae4-b194-3398474315a2" xlink:to="loc_us-gaap_OtherCommitmentsDomain_6dbb830e-fa26-4ccf-9a95-fa25bb954833" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_PrepaymentsOfFutureDepreciationMember_b4711054-addf-4c7b-a565-ebfc236b6066" xlink:href="wdc-20210402.xsd#wdc_PrepaymentsOfFutureDepreciationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_6dbb830e-fa26-4ccf-9a95-fa25bb954833" xlink:to="loc_wdc_PrepaymentsOfFutureDepreciationMember_b4711054-addf-4c7b-a565-ebfc236b6066" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_ec8729b4-3d52-4adc-aec9-3e556f39bc98" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_dei_LegalEntityAxis_ec8729b4-3d52-4adc-aec9-3e556f39bc98" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_ec8729b4-3d52-4adc-aec9-3e556f39bc98_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_ec8729b4-3d52-4adc-aec9-3e556f39bc98" xlink:to="loc_dei_EntityDomain_ec8729b4-3d52-4adc-aec9-3e556f39bc98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_403a714c-37b3-48f7-a3f9-d9950048c562" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_ec8729b4-3d52-4adc-aec9-3e556f39bc98" xlink:to="loc_dei_EntityDomain_403a714c-37b3-48f7-a3f9-d9950048c562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_UnissoftWuxiGroupCoLtd.Member_2c18e29c-d45b-4251-a5a0-634f241085c6" xlink:href="wdc-20210402.xsd#wdc_UnissoftWuxiGroupCoLtd.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_403a714c-37b3-48f7-a3f9-d9950048c562" xlink:to="loc_wdc_UnissoftWuxiGroupCoLtd.Member_2c18e29c-d45b-4251-a5a0-634f241085c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eec1d350-0528-4e5e-871d-bacca25b08ae" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eec1d350-0528-4e5e-871d-bacca25b08ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_eec1d350-0528-4e5e-871d-bacca25b08ae_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eec1d350-0528-4e5e-871d-bacca25b08ae" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_eec1d350-0528-4e5e-871d-bacca25b08ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_45e10803-53c1-4f8a-adc2-ef89cbeaed10" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eec1d350-0528-4e5e-871d-bacca25b08ae" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_45e10803-53c1-4f8a-adc2-ef89cbeaed10" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_FlashVenturesMember_8e04f011-c645-4d87-8c1c-60bd4393348b" xlink:href="wdc-20210402.xsd#wdc_FlashVenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_45e10803-53c1-4f8a-adc2-ef89cbeaed10" xlink:to="loc_wdc_FlashVenturesMember_8e04f011-c645-4d87-8c1c-60bd4393348b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_UnisVentureMember_45be4fbf-7df3-4376-8a82-5236b4d7219d" xlink:href="wdc-20210402.xsd#wdc_UnisVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_45e10803-53c1-4f8a-adc2-ef89cbeaed10" xlink:to="loc_wdc_UnisVentureMember_45be4fbf-7df3-4376-8a82-5236b4d7219d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2b18e647-513a-4de7-b21f-c8fd2a737225" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2b18e647-513a-4de7-b21f-c8fd2a737225" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_2b18e647-513a-4de7-b21f-c8fd2a737225_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2b18e647-513a-4de7-b21f-c8fd2a737225" xlink:to="loc_us-gaap_RelatedPartyDomain_2b18e647-513a-4de7-b21f-c8fd2a737225_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_ed904ab6-9cee-4a2d-9c84-f06767a9fb68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2b18e647-513a-4de7-b21f-c8fd2a737225" xlink:to="loc_us-gaap_RelatedPartyDomain_ed904ab6-9cee-4a2d-9c84-f06767a9fb68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_dca7d5c1-2d2f-4765-84f4-aae235936670" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_ed904ab6-9cee-4a2d-9c84-f06767a9fb68" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_dca7d5c1-2d2f-4765-84f4-aae235936670" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EquityMethodInvestorNameAxis_1adf3129-6bb1-415c-ac83-2fb443cafe78" xlink:href="wdc-20210402.xsd#wdc_EquityMethodInvestorNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_wdc_EquityMethodInvestorNameAxis_1adf3129-6bb1-415c-ac83-2fb443cafe78" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EquityMethodInvestorNameDomain_1adf3129-6bb1-415c-ac83-2fb443cafe78_default" xlink:href="wdc-20210402.xsd#wdc_EquityMethodInvestorNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_wdc_EquityMethodInvestorNameAxis_1adf3129-6bb1-415c-ac83-2fb443cafe78" xlink:to="loc_wdc_EquityMethodInvestorNameDomain_1adf3129-6bb1-415c-ac83-2fb443cafe78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EquityMethodInvestorNameDomain_2d77ba2d-ef2e-4a20-9c55-aeeb30fc3d81" xlink:href="wdc-20210402.xsd#wdc_EquityMethodInvestorNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_wdc_EquityMethodInvestorNameAxis_1adf3129-6bb1-415c-ac83-2fb443cafe78" xlink:to="loc_wdc_EquityMethodInvestorNameDomain_2d77ba2d-ef2e-4a20-9c55-aeeb30fc3d81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_WesternDigitalCorpMember_08bc00c1-d6f1-41cc-8838-76c98ebe7bc7" xlink:href="wdc-20210402.xsd#wdc_WesternDigitalCorpMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wdc_EquityMethodInvestorNameDomain_2d77ba2d-ef2e-4a20-9c55-aeeb30fc3d81" xlink:to="loc_wdc_WesternDigitalCorpMember_08bc00c1-d6f1-41cc-8838-76c98ebe7bc7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2bc9d9a5-8a06-4695-9889-c48528f9cbb3" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_srt_RangeAxis_2bc9d9a5-8a06-4695-9889-c48528f9cbb3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2bc9d9a5-8a06-4695-9889-c48528f9cbb3_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2bc9d9a5-8a06-4695-9889-c48528f9cbb3" xlink:to="loc_srt_RangeMember_2bc9d9a5-8a06-4695-9889-c48528f9cbb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_42943c75-6e86-4bd9-a8cd-e2063d5c3037" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2bc9d9a5-8a06-4695-9889-c48528f9cbb3" xlink:to="loc_srt_RangeMember_42943c75-6e86-4bd9-a8cd-e2063d5c3037" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_cb2f02ed-d48e-415e-9c9d-61caf7bb7fc5" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_42943c75-6e86-4bd9-a8cd-e2063d5c3037" xlink:to="loc_srt_MinimumMember_cb2f02ed-d48e-415e-9c9d-61caf7bb7fc5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_575c6b4b-b920-49c1-9167-63773a09447a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_42943c75-6e86-4bd9-a8cd-e2063d5c3037" xlink:to="loc_srt_MaximumMember_575c6b4b-b920-49c1-9167-63773a09447a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_4e5f9db8-cc42-4481-9a47-3b78ba902988" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_4e5f9db8-cc42-4481-9a47-3b78ba902988" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_4e5f9db8-cc42-4481-9a47-3b78ba902988_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4e5f9db8-cc42-4481-9a47-3b78ba902988" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_4e5f9db8-cc42-4481-9a47-3b78ba902988_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_d8dd683e-7e84-48ce-9c2b-1c50eb667bbb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4e5f9db8-cc42-4481-9a47-3b78ba902988" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_d8dd683e-7e84-48ce-9c2b-1c50eb667bbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductConcentrationRiskMember_fbfc09d7-164b-4875-bde3-4fa6564f33aa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_d8dd683e-7e84-48ce-9c2b-1c50eb667bbb" xlink:to="loc_us-gaap_ProductConcentrationRiskMember_fbfc09d7-164b-4875-bde3-4fa6564f33aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6e335fb0-a2f0-4bd3-9548-4683707e216a" xlink:to="loc_srt_MajorCustomersAxis_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1" xlink:to="loc_srt_NameOfMajorCustomerDomain_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_fbbe2bd1-b7be-48d2-8911-066009fcdc5c" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_d8c5aace-34f2-41a2-ada9-ba80b7eac0a1" xlink:to="loc_srt_NameOfMajorCustomerDomain_fbbe2bd1-b7be-48d2-8911-066009fcdc5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_UnisVentureMember_e66dd9b1-fdca-4247-8337-809475981726" xlink:href="wdc-20210402.xsd#wdc_UnisVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_fbbe2bd1-b7be-48d2-8911-066009fcdc5c" xlink:to="loc_wdc_UnisVentureMember_e66dd9b1-fdca-4247-8337-809475981726" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesMaximumLossExposureDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesMaximumLossExposureDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesMaximumLossExposureDetails" xlink:type="extended" id="iec5b754630814c87af1c0f8a90954fd4_RelatedPartiesandRelatedCommitmentsandContingenciesMaximumLossExposureDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_d688a5da-52f6-4d89-b849-b381b7dbef37" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_56425fac-859e-4e99-abc3-da65a9bf0218" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_d688a5da-52f6-4d89-b849-b381b7dbef37" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_56425fac-859e-4e99-abc3-da65a9bf0218" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_f50704df-2ad4-4f51-a465-df4be089bacf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_d688a5da-52f6-4d89-b849-b381b7dbef37" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_f50704df-2ad4-4f51-a465-df4be089bacf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryGross_f49c8f90-fab6-49fc-a3cd-64a6d74914e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_d688a5da-52f6-4d89-b849-b381b7dbef37" xlink:to="loc_us-gaap_InventoryGross_f49c8f90-fab6-49fc-a3cd-64a6d74914e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_b92a83b2-d243-44da-8200-f23339f0f7fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_d688a5da-52f6-4d89-b849-b381b7dbef37" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_b92a83b2-d243-44da-8200-f23339f0f7fa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_b92a83b2-d243-44da-8200-f23339f0f7fa" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_ff13e8b6-57f5-4e6d-bb68-6b54774d4b41" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableMember_d934c743-9e41-496b-9648-9040768c7739" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:to="loc_us-gaap_NotesReceivableMember_d934c743-9e41-496b-9648-9040768c7739" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_9f333f68-c842-4fca-811c-7af84461dee5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:to="loc_us-gaap_EquityMethodInvestmentsMember_9f333f68-c842-4fca-811c-7af84461dee5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OffBalanceSheetGuaranteeMember_11bcc35d-cdd2-4bcc-b3f5-9c83e1616889" xlink:href="wdc-20210402.xsd#wdc_OffBalanceSheetGuaranteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:to="loc_wdc_OffBalanceSheetGuaranteeMember_11bcc35d-cdd2-4bcc-b3f5-9c83e1616889" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember_d24d68a2-6154-4f57-975b-2a69820ed8e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6e6485b0-eb22-4f2a-9794-15f6da2edbcb" xlink:to="loc_us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember_d24d68a2-6154-4f57-975b-2a69820ed8e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_de6b57b0-8006-4a91-903a-28b80b17030e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_b92a83b2-d243-44da-8200-f23339f0f7fa" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_de6b57b0-8006-4a91-903a-28b80b17030e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_de6b57b0-8006-4a91-903a-28b80b17030e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_de6b57b0-8006-4a91-903a-28b80b17030e" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_de6b57b0-8006-4a91-903a-28b80b17030e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_d3d339bb-8f5b-4087-b3dc-4fcae9267ea7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_de6b57b0-8006-4a91-903a-28b80b17030e" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_d3d339bb-8f5b-4087-b3dc-4fcae9267ea7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_f4735866-9b2d-4d04-a1b4-f79e2b00303f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_d3d339bb-8f5b-4087-b3dc-4fcae9267ea7" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_f4735866-9b2d-4d04-a1b4-f79e2b00303f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesJVLeaseGuaranteesDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesJVLeaseGuaranteesDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesJVLeaseGuaranteesDetails" xlink:type="extended" id="i3dfffc8bda0d40edafa0a35068ae766e_RelatedPartiesandRelatedCommitmentsandContingenciesJVLeaseGuaranteesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_11caa8c5-2abc-48b6-b347-3dd08e0ae1eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_07cc598e-d5fa-4008-8329-658ee520f48d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_11caa8c5-2abc-48b6-b347-3dd08e0ae1eb" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_07cc598e-d5fa-4008-8329-658ee520f48d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_4edff9aa-1f78-4065-a381-14167f31b811" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_11caa8c5-2abc-48b6-b347-3dd08e0ae1eb" xlink:to="loc_us-gaap_LossContingenciesTable_4edff9aa-1f78-4065-a381-14167f31b811" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_6cec5b03-65f5-4d12-967c-fed53e3b96a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_4edff9aa-1f78-4065-a381-14167f31b811" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_6cec5b03-65f5-4d12-967c-fed53e3b96a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6cec5b03-65f5-4d12-967c-fed53e3b96a5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6cec5b03-65f5-4d12-967c-fed53e3b96a5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6cec5b03-65f5-4d12-967c-fed53e3b96a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_2af6628d-69fa-453d-8bbf-fdb7f7941673" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6cec5b03-65f5-4d12-967c-fed53e3b96a5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_2af6628d-69fa-453d-8bbf-fdb7f7941673" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_OffBalanceSheetGuaranteeMember_6540efd5-5ac4-4a11-a8a8-fea2044c2d0a" xlink:href="wdc-20210402.xsd#wdc_OffBalanceSheetGuaranteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_2af6628d-69fa-453d-8bbf-fdb7f7941673" xlink:to="loc_wdc_OffBalanceSheetGuaranteeMember_6540efd5-5ac4-4a11-a8a8-fea2044c2d0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_40e66b49-764a-4dbc-a315-305020b1a780" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_4edff9aa-1f78-4065-a381-14167f31b811" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_40e66b49-764a-4dbc-a315-305020b1a780" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_40e66b49-764a-4dbc-a315-305020b1a780_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_40e66b49-764a-4dbc-a315-305020b1a780" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_40e66b49-764a-4dbc-a315-305020b1a780_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_47030f41-6567-498f-b8ff-167455d75d4d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_40e66b49-764a-4dbc-a315-305020b1a780" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_47030f41-6567-498f-b8ff-167455d75d4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_5e958f84-9e0b-4ebe-9806-73e587767d21" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_47030f41-6567-498f-b8ff-167455d75d4d" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_5e958f84-9e0b-4ebe-9806-73e587767d21" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesJointVentureLeaseAmountsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesJointVentureLeaseAmountsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesJointVentureLeaseAmountsDetails" xlink:type="extended" id="i7befca8789cd4658b38c4d9c12a86fe4_RelatedPartiesandRelatedCommitmentsandContingenciesJointVentureLeaseAmountsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureRemainderOfFiscalYear_0877ddc0-d8fa-48e5-998f-8c9cd7067eda" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureRemainderOfFiscalYear_0877ddc0-d8fa-48e5-998f-8c9cd7067eda" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureYearOne_276cd043-79f7-4155-993b-d50d200319cd" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureYearOne_276cd043-79f7-4155-993b-d50d200319cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureYearTwo_7866d7ef-abad-4b5d-9d28-78859647b3a0" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureYearTwo_7866d7ef-abad-4b5d-9d28-78859647b3a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureYearThree_1bcaa089-be91-42d3-90af-ab9ddbe54eb9" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureYearThree_1bcaa089-be91-42d3-90af-ab9ddbe54eb9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureYearFour_17deacb4-4165-4bbf-b251-aa0457732ad9" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureYearFour_17deacb4-4165-4bbf-b251-aa0457732ad9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_GuaranteeObligationsMaximumExposureThereafter_7d8f4329-8eaa-497b-bef5-5f69fb60fc0b" xlink:href="wdc-20210402.xsd#wdc_GuaranteeObligationsMaximumExposureThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_wdc_GuaranteeObligationsMaximumExposureThereafter_7d8f4329-8eaa-497b-bef5-5f69fb60fc0b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_525de24d-85e6-4f11-973d-50abdfd0ea50" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_525de24d-85e6-4f11-973d-50abdfd0ea50" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_94774e14-21f2-4a58-abf2-d1543f3ebfa4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_dd74d77c-5182-4406-97e8-e14427399e2f" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_94774e14-21f2-4a58-abf2-d1543f3ebfa4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_40cf11a2-f949-40cb-80b2-977b710c8e1f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_94774e14-21f2-4a58-abf2-d1543f3ebfa4" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_40cf11a2-f949-40cb-80b2-977b710c8e1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_40cf11a2-f949-40cb-80b2-977b710c8e1f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_40cf11a2-f949-40cb-80b2-977b710c8e1f" xlink:to="loc_us-gaap_RelatedPartyDomain_40cf11a2-f949-40cb-80b2-977b710c8e1f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_763e12c4-c631-45ec-bfc0-e9b1feec6852" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_40cf11a2-f949-40cb-80b2-977b710c8e1f" xlink:to="loc_us-gaap_RelatedPartyDomain_763e12c4-c631-45ec-bfc0-e9b1feec6852" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_17cfa67e-145f-434c-b28a-857ea6db004f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_763e12c4-c631-45ec-bfc0-e9b1feec6852" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_17cfa67e-145f-434c-b28a-857ea6db004f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_6ce83d7e-cab6-46f1-a399-dc4a6b39003d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_94774e14-21f2-4a58-abf2-d1543f3ebfa4" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_6ce83d7e-cab6-46f1-a399-dc4a6b39003d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_6ce83d7e-cab6-46f1-a399-dc4a6b39003d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_6ce83d7e-cab6-46f1-a399-dc4a6b39003d" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_6ce83d7e-cab6-46f1-a399-dc4a6b39003d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_659a538d-ffb9-4d21-a577-df37f3b7c64d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_6ce83d7e-cab6-46f1-a399-dc4a6b39003d" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_659a538d-ffb9-4d21-a577-df37f3b7c64d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_PaymentOfPrincipalAmortizationMember_954245d6-928f-4c4e-8e03-94fed1cc96b6" xlink:href="wdc-20210402.xsd#wdc_PaymentOfPrincipalAmortizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_659a538d-ffb9-4d21-a577-df37f3b7c64d" xlink:to="loc_wdc_PaymentOfPrincipalAmortizationMember_954245d6-928f-4c4e-8e03-94fed1cc96b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_PurchaseOptionExercisePriceMember_6c985520-0ab3-48fa-a26f-8d90d0cc2e79" xlink:href="wdc-20210402.xsd#wdc_PurchaseOptionExercisePriceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_659a538d-ffb9-4d21-a577-df37f3b7c64d" xlink:to="loc_wdc_PurchaseOptionExercisePriceMember_6c985520-0ab3-48fa-a26f-8d90d0cc2e79" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/LeasesandOtherCommitments" xlink:type="simple" xlink:href="wdc-20210402.xsd#LeasesandOtherCommitments"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LeasesandOtherCommitments" xlink:type="extended" id="ifb738cacf6174dc4aaac66d898c7758e_LeasesandOtherCommitments"/>
  <link:roleRef roleURI="http://www.wdc.com/role/LeasesandOtherCommitmentsTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#LeasesandOtherCommitmentsTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LeasesandOtherCommitmentsTables" xlink:type="extended" id="iba35b817bb924b0ea457688f531ae7fc_LeasesandOtherCommitmentsTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/LeasesandOtherCommitmentsSupplementalBalanceSheetDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#LeasesandOtherCommitmentsSupplementalBalanceSheetDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LeasesandOtherCommitmentsSupplementalBalanceSheetDetails" xlink:type="extended" id="ifafe12e1315d478eb5e8c86ae4af9a77_LeasesandOtherCommitmentsSupplementalBalanceSheetDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/LeasesandOtherCommitmentsSupplementalCashFlowDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#LeasesandOtherCommitmentsSupplementalCashFlowDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LeasesandOtherCommitmentsSupplementalCashFlowDetails" xlink:type="extended" id="ief9e757604474735996ca92dcd6df951_LeasesandOtherCommitmentsSupplementalCashFlowDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/LeasesandOtherCommitmentsLongTermCommitmentsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#LeasesandOtherCommitmentsLongTermCommitmentsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LeasesandOtherCommitmentsLongTermCommitmentsDetails" xlink:type="extended" id="ia9f01b45a00640648b144fcc0c1cc4c5_LeasesandOtherCommitmentsLongTermCommitmentsDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquity" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquity"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquity" xlink:type="extended" id="i36455e2253c74867b8d200fcf722687a_ShareholdersEquity"/>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityTables" xlink:type="extended" id="ia7437b25f938447ea94a442b87c2bfa1_ShareholdersEquityTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityStockBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityStockBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityStockBasedCompensationExpenseDetails" xlink:type="extended" id="ie8d9f84f47704d69b39f255796ebd0fb_ShareholdersEquityStockBasedCompensationExpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_03b39f65-c6db-49eb-a3f9-f51c3de3b1b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_cf0cdfee-9de8-483e-a494-89f30814e30c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_03b39f65-c6db-49eb-a3f9-f51c3de3b1b4" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_cf0cdfee-9de8-483e-a494-89f30814e30c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_1b7aa39e-25ab-410d-a481-ea84463e19e3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_03b39f65-c6db-49eb-a3f9-f51c3de3b1b4" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_1b7aa39e-25ab-410d-a481-ea84463e19e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_0d2af33a-75ef-4fb7-b6bf-c25de3493266" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_03b39f65-c6db-49eb-a3f9-f51c3de3b1b4" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_0d2af33a-75ef-4fb7-b6bf-c25de3493266" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_49dfa282-221a-4e50-a006-64a4f49d1c90" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_03b39f65-c6db-49eb-a3f9-f51c3de3b1b4" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_49dfa282-221a-4e50-a006-64a4f49d1c90" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_276a6949-5238-41b6-96c4-e74cf3760d5a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_49dfa282-221a-4e50-a006-64a4f49d1c90" xlink:to="loc_us-gaap_AwardTypeAxis_276a6949-5238-41b6-96c4-e74cf3760d5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_276a6949-5238-41b6-96c4-e74cf3760d5a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_276a6949-5238-41b6-96c4-e74cf3760d5a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_276a6949-5238-41b6-96c4-e74cf3760d5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_40a52bb3-3d41-463f-b191-0a75bef9c495" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_276a6949-5238-41b6-96c4-e74cf3760d5a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_40a52bb3-3d41-463f-b191-0a75bef9c495" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_506f7e84-6d44-439b-8a61-63db652a7748" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_40a52bb3-3d41-463f-b191-0a75bef9c495" xlink:to="loc_us-gaap_EmployeeStockOptionMember_506f7e84-6d44-439b-8a61-63db652a7748" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_306c6fed-ae3d-4266-be17-772f33c39410" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_40a52bb3-3d41-463f-b191-0a75bef9c495" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_306c6fed-ae3d-4266-be17-772f33c39410" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EmployeeStockPurchasePlanMember_9252e2b7-c336-4880-a78b-b24fd98982d1" xlink:href="wdc-20210402.xsd#wdc_EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_40a52bb3-3d41-463f-b191-0a75bef9c495" xlink:to="loc_wdc_EmployeeStockPurchasePlanMember_9252e2b7-c336-4880-a78b-b24fd98982d1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_4453ba76-47ec-4c00-9151-7cbf6d9c5f85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_49dfa282-221a-4e50-a006-64a4f49d1c90" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_4453ba76-47ec-4c00-9151-7cbf6d9c5f85" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_4453ba76-47ec-4c00-9151-7cbf6d9c5f85_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4453ba76-47ec-4c00-9151-7cbf6d9c5f85" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_4453ba76-47ec-4c00-9151-7cbf6d9c5f85_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_21caf8e6-bd1e-4906-bf4a-f5338a95e477" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4453ba76-47ec-4c00-9151-7cbf6d9c5f85" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_21caf8e6-bd1e-4906-bf4a-f5338a95e477" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_c201b8c8-010f-4fa4-bc2d-f52601d38736" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21caf8e6-bd1e-4906-bf4a-f5338a95e477" xlink:to="loc_us-gaap_CostOfSalesMember_c201b8c8-010f-4fa4-bc2d-f52601d38736" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_b0629618-b8dd-47d3-a93f-216730cd4a99" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21caf8e6-bd1e-4906-bf4a-f5338a95e477" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_b0629618-b8dd-47d3-a93f-216730cd4a99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_b3354612-d68d-4304-bdf6-67e6a1c26e6e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21caf8e6-bd1e-4906-bf4a-f5338a95e477" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_b3354612-d68d-4304-bdf6-67e6a1c26e6e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityUnrecognizedSharebasedCompensationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityUnrecognizedSharebasedCompensationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityUnrecognizedSharebasedCompensationDetails" xlink:type="extended" id="if4a4d0b093034f268ab3e4b430bb9072_ShareholdersEquityUnrecognizedSharebasedCompensationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1fb15ba-a534-4b1f-96e2-cfc306602cb9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_c25187a4-95d0-4f15-84c5-5ffbb1e8cf53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1fb15ba-a534-4b1f-96e2-cfc306602cb9" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_c25187a4-95d0-4f15-84c5-5ffbb1e8cf53" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_34e439e4-4081-4bb6-a26b-535fa1d50a96" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1fb15ba-a534-4b1f-96e2-cfc306602cb9" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_34e439e4-4081-4bb6-a26b-535fa1d50a96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0b7f8214-c5b2-49cc-b16e-aa47934b7f58" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1fb15ba-a534-4b1f-96e2-cfc306602cb9" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0b7f8214-c5b2-49cc-b16e-aa47934b7f58" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_e305125b-a78d-463f-b5c7-7e40c53744fc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0b7f8214-c5b2-49cc-b16e-aa47934b7f58" xlink:to="loc_us-gaap_AwardTypeAxis_e305125b-a78d-463f-b5c7-7e40c53744fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e305125b-a78d-463f-b5c7-7e40c53744fc_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_e305125b-a78d-463f-b5c7-7e40c53744fc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e305125b-a78d-463f-b5c7-7e40c53744fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4993fa76-c4e1-480a-882f-f6d278b5e443" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_e305125b-a78d-463f-b5c7-7e40c53744fc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4993fa76-c4e1-480a-882f-f6d278b5e443" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_4b9f85f3-5be0-4c26-b563-456b893c5456" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4993fa76-c4e1-480a-882f-f6d278b5e443" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_4b9f85f3-5be0-4c26-b563-456b893c5456" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EmployeeStockPurchasePlanMember_61c314f1-a4cc-48ce-aa4e-9b4b55e5d314" xlink:href="wdc-20210402.xsd#wdc_EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4993fa76-c4e1-480a-882f-f6d278b5e443" xlink:to="loc_wdc_EmployeeStockPurchasePlanMember_61c314f1-a4cc-48ce-aa4e-9b4b55e5d314" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityStockOptionActivityDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityStockOptionActivityDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityStockOptionActivityDetails" xlink:type="extended" id="ica90a0b78fdf441fb72c4a45482a888d_ShareholdersEquityStockOptionActivityDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityRestrictedStockUnitsAndPerformanceShareUnitsDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityRestrictedStockUnitsAndPerformanceShareUnitsDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityRestrictedStockUnitsAndPerformanceShareUnitsDetails" xlink:type="extended" id="i4134a383a3d746a9af75b1571234c972_ShareholdersEquityRestrictedStockUnitsAndPerformanceShareUnitsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1cafd19b-4ac0-48e5-8c4f-115fe56b3a81" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1cafd19b-4ac0-48e5-8c4f-115fe56b3a81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8aa18229-5707-4b96-8817-54ba841c7120" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8aa18229-5707-4b96-8817-54ba841c7120" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_854ba397-b6c1-47f3-a02f-746f13b6af57" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_854ba397-b6c1-47f3-a02f-746f13b6af57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_11aee0a9-cdcf-4f9b-b8d0-503eb1c9c689" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_11aee0a9-cdcf-4f9b-b8d0-503eb1c9c689" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7e261daf-d80e-4fd5-b24c-6e37c3443f0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8416c5cb-7e73-478c-9eba-803868687a65" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7e261daf-d80e-4fd5-b24c-6e37c3443f0c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_62055e02-c9d9-4e4b-80a9-4e0ddc30d4fe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1cafd19b-4ac0-48e5-8c4f-115fe56b3a81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_31468b06-9197-4f40-b3c0-9d65fbe11739" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_31468b06-9197-4f40-b3c0-9d65fbe11739" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_30735678-34e5-4e29-aef8-aabfd1a27f5a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_30735678-34e5-4e29-aef8-aabfd1a27f5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_218a1c19-2ef1-49e3-8d4a-ff6f3e0a6775" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_218a1c19-2ef1-49e3-8d4a-ff6f3e0a6775" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ShareBasedCompensationArrangementByShareBasedPaymentAwardsEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue_6cc4c2bd-2f78-4316-a34a-cb2ea26929dc" xlink:href="wdc-20210402.xsd#wdc_ShareBasedCompensationArrangementByShareBasedPaymentAwardsEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_c261d4ee-ca11-476c-ba1f-10c086989842" xlink:to="loc_wdc_ShareBasedCompensationArrangementByShareBasedPaymentAwardsEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue_6cc4c2bd-2f78-4316-a34a-cb2ea26929dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ace2e98c-f61c-444a-8e2a-eb7505233aab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_AggregateValueOfRestrictedStockAwardsVested_e3cadbcb-319e-4210-a4cc-4bc854f98fe5" xlink:href="wdc-20210402.xsd#wdc_AggregateValueOfRestrictedStockAwardsVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1cafd19b-4ac0-48e5-8c4f-115fe56b3a81" xlink:to="loc_wdc_AggregateValueOfRestrictedStockAwardsVested_e3cadbcb-319e-4210-a4cc-4bc854f98fe5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_efdeca35-0ac8-487d-a104-13acb5a77a70" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1cafd19b-4ac0-48e5-8c4f-115fe56b3a81" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_efdeca35-0ac8-487d-a104-13acb5a77a70" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_4b481ac7-0451-47cd-870a-872a8e6da425" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_efdeca35-0ac8-487d-a104-13acb5a77a70" xlink:to="loc_us-gaap_AwardTypeAxis_4b481ac7-0451-47cd-870a-872a8e6da425" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b481ac7-0451-47cd-870a-872a8e6da425_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_4b481ac7-0451-47cd-870a-872a8e6da425" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b481ac7-0451-47cd-870a-872a8e6da425_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6743086e-2609-4952-9821-a513cefe7127" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_4b481ac7-0451-47cd-870a-872a8e6da425" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6743086e-2609-4952-9821-a513cefe7127" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_RestrictedStockUnitsAndPerformanceShareUnitsMember_ac93392e-b176-493a-8684-122f4e95eefd" xlink:href="wdc-20210402.xsd#wdc_RestrictedStockUnitsAndPerformanceShareUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6743086e-2609-4952-9821-a513cefe7127" xlink:to="loc_wdc_RestrictedStockUnitsAndPerformanceShareUnitsMember_ac93392e-b176-493a-8684-122f4e95eefd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/ShareholdersEquityShareRepurchaseProgramDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#ShareholdersEquityShareRepurchaseProgramDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/ShareholdersEquityShareRepurchaseProgramDetails" xlink:type="extended" id="i746f4c3749994bd4a0f60c638b0a5d21_ShareholdersEquityShareRepurchaseProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityClassOfTreasuryStockLineItems_d569a57c-69da-439c-854f-c91a44d596eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityClassOfTreasuryStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_4c41e3fd-b8c4-42d7-860e-0a3a26d309e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_d569a57c-69da-439c-854f-c91a44d596eb" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_4c41e3fd-b8c4-42d7-860e-0a3a26d309e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_a4ab368c-0dc2-451e-b939-e5527e42e238" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_d569a57c-69da-439c-854f-c91a44d596eb" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_a4ab368c-0dc2-451e-b939-e5527e42e238" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfTreasuryStockTable_886838c1-3ea2-44dc-a92f-1f134843f29d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfTreasuryStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_d569a57c-69da-439c-854f-c91a44d596eb" xlink:to="loc_us-gaap_ClassOfTreasuryStockTable_886838c1-3ea2-44dc-a92f-1f134843f29d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_194e7876-081d-4215-a073-1ec8fa53ecad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_886838c1-3ea2-44dc-a92f-1f134843f29d" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_194e7876-081d-4215-a073-1ec8fa53ecad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_194e7876-081d-4215-a073-1ec8fa53ecad_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_194e7876-081d-4215-a073-1ec8fa53ecad" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_194e7876-081d-4215-a073-1ec8fa53ecad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_7acf88c0-4583-4605-b79f-030a9e12c9ee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_194e7876-081d-4215-a073-1ec8fa53ecad" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_7acf88c0-4583-4605-b79f-030a9e12c9ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_StockRepurchaseProgramEffectiveUntilJuly252023Member_91f391d3-01f9-46db-b9c9-d0ae9b414651" xlink:href="wdc-20210402.xsd#wdc_StockRepurchaseProgramEffectiveUntilJuly252023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_7acf88c0-4583-4605-b79f-030a9e12c9ee" xlink:to="loc_wdc_StockRepurchaseProgramEffectiveUntilJuly252023Member_91f391d3-01f9-46db-b9c9-d0ae9b414651" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ShareRepurchaseProgramMember_d86a1709-9af2-4f48-b03e-e4b11a8078b3" xlink:href="wdc-20210402.xsd#wdc_ShareRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_7acf88c0-4583-4605-b79f-030a9e12c9ee" xlink:to="loc_wdc_ShareRepurchaseProgramMember_d86a1709-9af2-4f48-b03e-e4b11a8078b3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/IncomeTaxExpense" xlink:type="simple" xlink:href="wdc-20210402.xsd#IncomeTaxExpense"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/IncomeTaxExpense" xlink:type="extended" id="idcab28b6ed9e4436ac81cf1c54b4e22f_IncomeTaxExpense"/>
  <link:roleRef roleURI="http://www.wdc.com/role/IncomeTaxExpenseTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#IncomeTaxExpenseTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/IncomeTaxExpenseTables" xlink:type="extended" id="i2297386fa90e43d78487a04983d3cbeb_IncomeTaxExpenseTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/IncomeTaxExpenseTaxExpenseandEffectiveTaxRateDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#IncomeTaxExpenseTaxExpenseandEffectiveTaxRateDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/IncomeTaxExpenseTaxExpenseandEffectiveTaxRateDetails" xlink:type="extended" id="if5f2d3c01df34ed2873ab99521fe632c_IncomeTaxExpenseTaxExpenseandEffectiveTaxRateDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/IncomeTaxExpenseAdditionalInformationDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#IncomeTaxExpenseAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/IncomeTaxExpenseAdditionalInformationDetails" xlink:type="extended" id="i13b3a10ffe8a499189655332245fd907_IncomeTaxExpenseAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities_7def22e9-103f-4d42-bba0-32f3feeae2f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromSettlementsWithTaxingAuthorities_7def22e9-103f-4d42-bba0-32f3feeae2f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_UnrecognizedTaxBenefitsDecreaseResultingFromRestructuringActivities_a9bbcfaa-ede6-4cab-b001-01b325f9453b" xlink:href="wdc-20210402.xsd#wdc_UnrecognizedTaxBenefitsDecreaseResultingFromRestructuringActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_UnrecognizedTaxBenefitsDecreaseResultingFromRestructuringActivities_a9bbcfaa-ede6-4cab-b001-01b325f9453b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_EffectiveIncomeTaxReconciliationDiscreteTaxEffectsNetTaxDeficiencies_19955660-bc64-48a9-9169-c818998714d3" xlink:href="wdc-20210402.xsd#wdc_EffectiveIncomeTaxReconciliationDiscreteTaxEffectsNetTaxDeficiencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_EffectiveIncomeTaxReconciliationDiscreteTaxEffectsNetTaxDeficiencies_19955660-bc64-48a9-9169-c818998714d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability_8639dfc0-0f9c-46b2-b707-1b81e6078310" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability_8639dfc0-0f9c-46b2-b707-1b81e6078310" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationEstimateOfPossibleLoss_a0b5c98f-e4c6-4d3a-9aa4-dee4eb9b2a48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_IncomeTaxExaminationEstimateOfPossibleLoss_a0b5c98f-e4c6-4d3a-9aa4-dee4eb9b2a48" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_IncomeTaxExaminationEstimateofPossibleLossResultingFromTransferPricingAdjustments_9e6fb5ca-9e19-4a7c-9a16-eabc35447d04" xlink:href="wdc-20210402.xsd#wdc_IncomeTaxExaminationEstimateofPossibleLossResultingFromTransferPricingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_IncomeTaxExaminationEstimateofPossibleLossResultingFromTransferPricingAdjustments_9e6fb5ca-9e19-4a7c-9a16-eabc35447d04" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_IncomeTaxExaminationPenaltiesAsserted_39168497-e055-49b1-9662-5249b668e40f" xlink:href="wdc-20210402.xsd#wdc_IncomeTaxExaminationPenaltiesAsserted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_IncomeTaxExaminationPenaltiesAsserted_39168497-e055-49b1-9662-5249b668e40f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_IncomeTaxExaminationAdditionalTax_0f1351f9-a94f-4547-a77a-0cb4d20914dd" xlink:href="wdc-20210402.xsd#wdc_IncomeTaxExaminationAdditionalTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_IncomeTaxExaminationAdditionalTax_0f1351f9-a94f-4547-a77a-0cb4d20914dd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationPenaltiesExpense_f1f390ab-2ef9-432a-9fb3-851e3020d383" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationPenaltiesExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_IncomeTaxExaminationPenaltiesExpense_f1f390ab-2ef9-432a-9fb3-851e3020d383" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_21a2a87b-d832-4bc1-aab3-6dc2cfb5b6f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_21a2a87b-d832-4bc1-aab3-6dc2cfb5b6f2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_87557c52-5169-49ea-8514-bb159a3daf10" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_87557c52-5169-49ea-8514-bb159a3daf10" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_UnrecognizedTaxBenefitsPayable_a329155b-8ef1-4c38-be14-a2243a3cf9e7" xlink:href="wdc-20210402.xsd#wdc_UnrecognizedTaxBenefitsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_wdc_UnrecognizedTaxBenefitsPayable_a329155b-8ef1-4c38-be14-a2243a3cf9e7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationTable_021fb764-a40b-474c-a9c4-2b3ca06ccd94" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_802faa60-a3d3-49f9-bb19-45a201d07d57" xlink:to="loc_us-gaap_IncomeTaxExaminationTable_021fb764-a40b-474c-a9c4-2b3ca06ccd94" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameAxis_aa15db2a-f322-48ff-a44e-731d7843ef69" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_021fb764-a40b-474c-a9c4-2b3ca06ccd94" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameAxis_aa15db2a-f322-48ff-a44e-731d7843ef69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_aa15db2a-f322-48ff-a44e-731d7843ef69_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_aa15db2a-f322-48ff-a44e-731d7843ef69" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_aa15db2a-f322-48ff-a44e-731d7843ef69_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_906238c0-2ff5-494c-8a88-bb586aa4c9ec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_aa15db2a-f322-48ff-a44e-731d7843ef69" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_906238c0-2ff5-494c-8a88-bb586aa4c9ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalRevenueServiceIRSMember_21658195-7556-4d48-97f7-060511eb184d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalRevenueServiceIRSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameDomain_906238c0-2ff5-494c-8a88-bb586aa4c9ec" xlink:to="loc_us-gaap_InternalRevenueServiceIRSMember_21658195-7556-4d48-97f7-060511eb184d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodAxis_1579b89a-7a93-48be-9f23-23915c96c5ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_021fb764-a40b-474c-a9c4-2b3ca06ccd94" xlink:to="loc_us-gaap_TaxPeriodAxis_1579b89a-7a93-48be-9f23-23915c96c5ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_1579b89a-7a93-48be-9f23-23915c96c5ca_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_1579b89a-7a93-48be-9f23-23915c96c5ca" xlink:to="loc_us-gaap_TaxPeriodDomain_1579b89a-7a93-48be-9f23-23915c96c5ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_8a5b02a0-ac04-4330-a45c-371a40041177" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_1579b89a-7a93-48be-9f23-23915c96c5ca" xlink:to="loc_us-gaap_TaxPeriodDomain_8a5b02a0-ac04-4330-a45c-371a40041177" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TaxYear2008Through2009Member_b10430eb-b663-4b0c-93fc-2d01bc02610f" xlink:href="wdc-20210402.xsd#wdc_TaxYear2008Through2009Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_8a5b02a0-ac04-4330-a45c-371a40041177" xlink:to="loc_wdc_TaxYear2008Through2009Member_b10430eb-b663-4b0c-93fc-2d01bc02610f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TaxYears2010Through2012Member_a60a94ff-10f2-48f3-80cd-ab030f267373" xlink:href="wdc-20210402.xsd#wdc_TaxYears2010Through2012Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_8a5b02a0-ac04-4330-a45c-371a40041177" xlink:to="loc_wdc_TaxYears2010Through2012Member_a60a94ff-10f2-48f3-80cd-ab030f267373" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_TaxYears2013Through2015Member_285fb698-e8f1-4030-8285-74cbaaa01cab" xlink:href="wdc-20210402.xsd#wdc_TaxYears2013Through2015Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_8a5b02a0-ac04-4330-a45c-371a40041177" xlink:to="loc_wdc_TaxYears2013Through2015Member_285fb698-e8f1-4030-8285-74cbaaa01cab" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/NetIncomeLossPerCommonShare" xlink:type="simple" xlink:href="wdc-20210402.xsd#NetIncomeLossPerCommonShare"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/NetIncomeLossPerCommonShare" xlink:type="extended" id="ibb3a4ad59da84cbb9c5cc1d56c6eaf44_NetIncomeLossPerCommonShare"/>
  <link:roleRef roleURI="http://www.wdc.com/role/NetIncomeLossPerCommonShareTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#NetIncomeLossPerCommonShareTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/NetIncomeLossPerCommonShareTables" xlink:type="extended" id="i488e19f1874a4a45b0a3d39f00a8b7ae_NetIncomeLossPerCommonShareTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/NetIncomeLossPerCommonShareDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#NetIncomeLossPerCommonShareDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/NetIncomeLossPerCommonShareDetails" xlink:type="extended" id="i60cc62dd696342f9b5090b9ed6982c67_NetIncomeLossPerCommonShareDetails"/>
  <link:roleRef roleURI="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherCharges" xlink:type="simple" xlink:href="wdc-20210402.xsd#EmployeeTerminationAssetImpairmentandOtherCharges"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherCharges" xlink:type="extended" id="i7986b9736fd543929b68abcd190a8059_EmployeeTerminationAssetImpairmentandOtherCharges"/>
  <link:roleRef roleURI="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesTables" xlink:type="simple" xlink:href="wdc-20210402.xsd#EmployeeTerminationAssetImpairmentandOtherChargesTables"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesTables" xlink:type="extended" id="i637b407f50f648a18f6675b5b19ec20f_EmployeeTerminationAssetImpairmentandOtherChargesTables"/>
  <link:roleRef roleURI="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesExpenseRecognitionDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#EmployeeTerminationAssetImpairmentandOtherChargesExpenseRecognitionDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesExpenseRecognitionDetails" xlink:type="extended" id="i1d288d2f950d437190c8d54a68d7b33f_EmployeeTerminationAssetImpairmentandOtherChargesExpenseRecognitionDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_d015830f-a325-4c08-9294-68545b55d727" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_9f4e4d36-5908-42d3-b5f6-d2a7b7024d14" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_d015830f-a325-4c08-9294-68545b55d727" xlink:to="loc_us-gaap_RestructuringCharges_9f4e4d36-5908-42d3-b5f6-d2a7b7024d14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssetsAbstract_384774b4-1177-46db-8839-7af48b66ccae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnDispositionOfAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_d015830f-a325-4c08-9294-68545b55d727" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssetsAbstract_384774b4-1177-46db-8839-7af48b66ccae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_cb63a5bd-cc35-432f-a735-3ec46e9c7f2d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainLossOnDispositionOfAssetsAbstract_384774b4-1177-46db-8839-7af48b66ccae" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_cb63a5bd-cc35-432f-a735-3ec46e9c7f2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_68bf00d3-dc1e-4214-ad95-426678c6740a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCostsAndAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainLossOnDispositionOfAssetsAbstract_384774b4-1177-46db-8839-7af48b66ccae" xlink:to="loc_us-gaap_RestructuringCostsAndAssetImpairmentCharges_68bf00d3-dc1e-4214-ad95-426678c6740a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_96de9561-8a26-4987-8e37-042ba8322ebb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_d015830f-a325-4c08-9294-68545b55d727" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_96de9561-8a26-4987-8e37-042ba8322ebb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanAxis_c9c576f5-552b-4f15-9ffc-c6173a791ceb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_96de9561-8a26-4987-8e37-042ba8322ebb" xlink:to="loc_us-gaap_RestructuringPlanAxis_c9c576f5-552b-4f15-9ffc-c6173a791ceb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_c9c576f5-552b-4f15-9ffc-c6173a791ceb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_c9c576f5-552b-4f15-9ffc-c6173a791ceb" xlink:to="loc_us-gaap_RestructuringPlanDomain_c9c576f5-552b-4f15-9ffc-c6173a791ceb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_2d412a35-8b7c-4713-a7f3-b6b9e8e132bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_c9c576f5-552b-4f15-9ffc-c6173a791ceb" xlink:to="loc_us-gaap_RestructuringPlanDomain_2d412a35-8b7c-4713-a7f3-b6b9e8e132bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_ClosureofForeignManufacturingFacilitiesMember_1d9d5ad6-f7fe-4be7-8ad5-09742d60a0b4" xlink:href="wdc-20210402.xsd#wdc_ClosureofForeignManufacturingFacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_2d412a35-8b7c-4713-a7f3-b6b9e8e132bc" xlink:to="loc_wdc_ClosureofForeignManufacturingFacilitiesMember_1d9d5ad6-f7fe-4be7-8ad5-09742d60a0b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_BusinessRealignmentActivitiesMember_640afa2d-fdd8-461e-9a70-7f112f92ce4f" xlink:href="wdc-20210402.xsd#wdc_BusinessRealignmentActivitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_2d412a35-8b7c-4713-a7f3-b6b9e8e132bc" xlink:to="loc_wdc_BusinessRealignmentActivitiesMember_640afa2d-fdd8-461e-9a70-7f112f92ce4f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesBusinessRealignmentActivitiesDetails" xlink:type="simple" xlink:href="wdc-20210402.xsd#EmployeeTerminationAssetImpairmentandOtherChargesBusinessRealignmentActivitiesDetails"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/EmployeeTerminationAssetImpairmentandOtherChargesBusinessRealignmentActivitiesDetails" xlink:type="extended" id="i8eb87c97866a4f1ebb2ec924f43fd613_EmployeeTerminationAssetImpairmentandOtherChargesBusinessRealignmentActivitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_b8ce8105-a963-4683-a47e-9bc16def810d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_c7e78574-f05e-4d6c-97f7-ce5ea650e2be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_b8ce8105-a963-4683-a47e-9bc16def810d" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_c7e78574-f05e-4d6c-97f7-ce5ea650e2be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_8156934d-1ab7-4a35-b5ca-070aab67b877" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_b8ce8105-a963-4683-a47e-9bc16def810d" xlink:to="loc_us-gaap_RestructuringReserveRollForward_8156934d-1ab7-4a35-b5ca-070aab67b877" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_30735689-1dc6-430c-a7f6-0b34b86a9f20" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8156934d-1ab7-4a35-b5ca-070aab67b877" xlink:to="loc_us-gaap_RestructuringReserve_30735689-1dc6-430c-a7f6-0b34b86a9f20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_cb5cc4e6-2017-45b4-8697-0ffaf6fa8db0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringAndRelatedCostIncurredCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8156934d-1ab7-4a35-b5ca-070aab67b877" xlink:to="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_cb5cc4e6-2017-45b4-8697-0ffaf6fa8db0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_f878926d-1a3b-41b9-abfa-3c2e2bb351ff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8156934d-1ab7-4a35-b5ca-070aab67b877" xlink:to="loc_us-gaap_PaymentsForRestructuring_f878926d-1a3b-41b9-abfa-3c2e2bb351ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_bc3b9d65-eaa4-4991-a8b4-92a1931f9a1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringReserve"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_42bfb6a7-c479-4bb9-96e8-f0d5b69b2975" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_b8ce8105-a963-4683-a47e-9bc16def810d" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_42bfb6a7-c479-4bb9-96e8-f0d5b69b2975" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_9a852fcc-d90e-4f7b-b798-a3e40e1711a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_42bfb6a7-c479-4bb9-96e8-f0d5b69b2975" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_9a852fcc-d90e-4f7b-b798-a3e40e1711a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_9a852fcc-d90e-4f7b-b798-a3e40e1711a9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_9a852fcc-d90e-4f7b-b798-a3e40e1711a9" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_9a852fcc-d90e-4f7b-b798-a3e40e1711a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_8b1edcff-28b0-4f58-b098-365ab70a118f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_9a852fcc-d90e-4f7b-b798-a3e40e1711a9" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_8b1edcff-28b0-4f58-b098-365ab70a118f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OneTimeTerminationBenefitsMember_8e9d9bf4-cf8c-4242-8833-9b2846b98c3a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OneTimeTerminationBenefitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_8b1edcff-28b0-4f58-b098-365ab70a118f" xlink:to="loc_us-gaap_OneTimeTerminationBenefitsMember_8e9d9bf4-cf8c-4242-8833-9b2846b98c3a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_2c723768-1b95-468e-9a84-823e728e3d3f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_8b1edcff-28b0-4f58-b098-365ab70a118f" xlink:to="loc_us-gaap_ContractTerminationMember_2c723768-1b95-468e-9a84-823e728e3d3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanAxis_5d135951-f9ff-4e54-bd6b-1c4ffcb30183" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_42bfb6a7-c479-4bb9-96e8-f0d5b69b2975" xlink:to="loc_us-gaap_RestructuringPlanAxis_5d135951-f9ff-4e54-bd6b-1c4ffcb30183" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_5d135951-f9ff-4e54-bd6b-1c4ffcb30183_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_5d135951-f9ff-4e54-bd6b-1c4ffcb30183" xlink:to="loc_us-gaap_RestructuringPlanDomain_5d135951-f9ff-4e54-bd6b-1c4ffcb30183_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_a7ddf710-1525-4263-b35b-5563fb1a3f1b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_5d135951-f9ff-4e54-bd6b-1c4ffcb30183" xlink:to="loc_us-gaap_RestructuringPlanDomain_a7ddf710-1525-4263-b35b-5563fb1a3f1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wdc_BusinessRealignmentActivitiesMember_3c4cd198-ef8f-4049-86bf-4a96139d1154" xlink:href="wdc-20210402.xsd#wdc_BusinessRealignmentActivitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_a7ddf710-1525-4263-b35b-5563fb1a3f1b" xlink:to="loc_wdc_BusinessRealignmentActivitiesMember_3c4cd198-ef8f-4049-86bf-4a96139d1154" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.wdc.com/role/LegalProceedings" xlink:type="simple" xlink:href="wdc-20210402.xsd#LegalProceedings"/>
  <link:definitionLink xlink:role="http://www.wdc.com/role/LegalProceedings" xlink:type="extended" id="if8133dab83564e0e81e77887d77cb5e8_LegalProceedings"/>
</link:linkbase>
