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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e2791-237a-7cf6-bdf6-caebd7b0a1de,g:7c272609-abe0-4fbd-bd4c-adafc8f78065-->
<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.dropbox.com/role/CoverPage" xlink:type="simple" xlink:href="dbx-20260630.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2531-76b9-ac3f-bad605e0821c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2531-76b9-ac3f-bad605e0821c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e2791-2531-7dcd-850a-7aacf793dc8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2531-76b9-ac3f-bad605e0821c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e2791-2531-7dcd-850a-7aacf793dc8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2531-7dcd-850a-7aacf793dc8b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2531-7dcd-850a-7aacf793dc8b" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2531-7dcd-850a-7aacf793dc8b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2531-737d-a6d5-59dd8092941e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2531-7dcd-850a-7aacf793dc8b" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2531-737d-a6d5-59dd8092941e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019e2791-2531-7bd4-a233-90deea30d17f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2531-737d-a6d5-59dd8092941e" xlink:to="loc_us-gaap_CommonClassAMember_019e2791-2531-7bd4-a233-90deea30d17f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019e2791-2531-7c89-9c5f-413ab823d59e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2531-737d-a6d5-59dd8092941e" xlink:to="loc_us-gaap_CommonClassBMember_019e2791-2531-7c89-9c5f-413ab823d59e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassCMember_019e2791-2531-7651-af14-e75ce27a9ada" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2531-737d-a6d5-59dd8092941e" xlink:to="loc_us-gaap_CommonClassCMember_019e2791-2531-7651-af14-e75ce27a9ada" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019e2791-2531-7cae-bdd2-78e8e9cd21e6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentType_019e2791-2531-7cae-bdd2-78e8e9cd21e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019e2791-2531-71e0-a94b-82f4d79a325e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentQuarterlyReport_019e2791-2531-71e0-a94b-82f4d79a325e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019e2791-2531-792f-83f9-b035ae125b84" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentPeriodEndDate_019e2791-2531-792f-83f9-b035ae125b84" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019e2791-2531-7c75-8fcc-a7bc481d7527" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentTransitionReport_019e2791-2531-7c75-8fcc-a7bc481d7527" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019e2791-2531-77ad-a366-906c7975371b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityFileNumber_019e2791-2531-77ad-a366-906c7975371b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019e2791-2531-7aaf-b1df-bd06ffb60cf4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityRegistrantName_019e2791-2531-7aaf-b1df-bd06ffb60cf4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019e2791-2531-71e3-95a2-343e59b659b5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019e2791-2531-71e3-95a2-343e59b659b5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019e2791-2531-7706-aef8-91eaa97c12f2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityTaxIdentificationNumber_019e2791-2531-7706-aef8-91eaa97c12f2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019e2791-2531-7679-a7b8-a515839bb4d9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityAddressAddressLine1_019e2791-2531-7679-a7b8-a515839bb4d9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019e2791-2531-72d4-9e0d-ae8d3dee9cbc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityAddressCityOrTown_019e2791-2531-72d4-9e0d-ae8d3dee9cbc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019e2791-2531-7d32-be5b-29c7a14be597" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityAddressStateOrProvince_019e2791-2531-7d32-be5b-29c7a14be597" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019e2791-2531-738a-806d-0c0c7ddd42ea" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityAddressPostalZipCode_019e2791-2531-738a-806d-0c0c7ddd42ea" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019e2791-2531-75e3-a686-3eca8475c35b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_CityAreaCode_019e2791-2531-75e3-a686-3eca8475c35b" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019e2791-2531-7596-aace-7dcb5f14e93d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_LocalPhoneNumber_019e2791-2531-7596-aace-7dcb5f14e93d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e2791-2531-7082-84e6-7dd17dd979b7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_Security12bTitle_019e2791-2531-7082-84e6-7dd17dd979b7" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e2791-2531-7ddd-ae7d-c9a8bcb00052" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_TradingSymbol_019e2791-2531-7ddd-ae7d-c9a8bcb00052" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e2791-2531-7fd1-a788-bb80decac149" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_SecurityExchangeName_019e2791-2531-7fd1-a788-bb80decac149" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019e2791-2531-77ce-b6f3-ed3edf35737a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityCurrentReportingStatus_019e2791-2531-77ce-b6f3-ed3edf35737a" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019e2791-2531-7090-a3fc-321c4308e005" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityInteractiveDataCurrent_019e2791-2531-7090-a3fc-321c4308e005" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019e2791-2531-7512-811c-5f7075174e82" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityFilerCategory_019e2791-2531-7512-811c-5f7075174e82" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019e2791-2531-753c-87b7-ed821236609d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntitySmallBusiness_019e2791-2531-753c-87b7-ed821236609d" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019e2791-2531-7ec4-80ba-b30538a8e3cb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityEmergingGrowthCompany_019e2791-2531-7ec4-80ba-b30538a8e3cb" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019e2791-2531-7a02-95b9-40a24b310577" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityShellCompany_019e2791-2531-7a02-95b9-40a24b310577" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019e2791-2531-74c7-a948-846b6e630c18" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019e2791-2531-74c7-a948-846b6e630c18" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019e2791-2531-7104-8a4d-731d8d8f4df2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_EntityCentralIndexKey_019e2791-2531-7104-8a4d-731d8d8f4df2" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019e2791-2531-765c-a1d9-ec9f527f55f0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_CurrentFiscalYearEndDate_019e2791-2531-765c-a1d9-ec9f527f55f0" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019e2791-2531-7904-b214-a0dbe4223c19" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentFiscalYearFocus_019e2791-2531-7904-b214-a0dbe4223c19" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019e2791-2531-79c9-a623-4b991d9f1ca6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019e2791-2531-79c9-a623-4b991d9f1ca6" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019e2791-2531-71ba-98f3-fcd91e7e82dc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2531-743a-b2e2-27bc4aa0cfe0" xlink:to="loc_dei_AmendmentFlag_019e2791-2531-71ba-98f3-fcd91e7e82dc" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical" xlink:type="simple" xlink:href="dbx-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3a98-e828-78da-92b1-188a110ef509" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:to="loc_us-gaap_StatementTable_019e3a98-e828-78da-92b1-188a110ef509" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e3b0c-4257-7928-985e-8dbb94066c01" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e3a98-e828-78da-92b1-188a110ef509" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e3b0c-4257-7928-985e-8dbb94066c01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e3a98-e828-754a-b43b-77f1ed9a329f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e3a98-e828-754a-b43b-77f1ed9a329f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical_1" xlink:type="simple" xlink:href="dbx-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical_1"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e3a98-e828-78da-92b1-188a110ef509" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:to="loc_us-gaap_StatementTable_019e3a98-e828-78da-92b1-188a110ef509" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e3a98-e828-754a-b43b-77f1ed9a329f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e3a98-e828-7239-8258-1ed18106ab11" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e3a98-e828-754a-b43b-77f1ed9a329f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSDEFICIT" xlink:type="simple" xlink:href="dbx-20260630.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSDEFICIT"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSDEFICIT" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e2791-2532-7b27-989f-478113a3b8b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e2791-2532-7af1-8636-3f754f65d85d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e2791-2532-7b27-989f-478113a3b8b2" xlink:to="loc_us-gaap_StatementTable_019e2791-2532-7af1-8636-3f754f65d85d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e2791-2532-7290-9292-15d154a4a3aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e2791-2532-7af1-8636-3f754f65d85d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e2791-2532-7290-9292-15d154a4a3aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e2791-2532-7290-9292-15d154a4a3aa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e2791-2532-7290-9292-15d154a4a3aa" xlink:to="loc_us-gaap_EquityComponentDomain_019e2791-2532-7290-9292-15d154a4a3aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e2791-2532-7290-9292-15d154a4a3aa" xlink:to="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e2791-2532-7691-8309-cba1e021fc8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:to="loc_us-gaap_CommonStockMember_019e2791-2532-7691-8309-cba1e021fc8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e2791-2532-7491-aa5b-e642d1112fde" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e2791-2532-7491-aa5b-e642d1112fde" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e2791-2532-78f5-b55a-fec63c9bbfbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:to="loc_us-gaap_RetainedEarningsMember_019e2791-2532-78f5-b55a-fec63c9bbfbf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e2791-2532-7fde-9db5-afba47c42949" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e2791-2532-762a-b57b-91768ad1003e" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e2791-2532-7fde-9db5-afba47c42949" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e2791-2532-7b27-989f-478113a3b8b2" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e2791-2532-79fa-8366-d129caad1c33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e2791-2532-79fa-8366-d129caad1c33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e2791-2532-7032-9ba2-9876294ffb35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_StockholdersEquity_019e2791-2532-7032-9ba2-9876294ffb35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SharesReleasedDuringPeriodShares_019e2791-2532-7908-b022-9e061470b5a0" xlink:href="dbx-20260630.xsd#dbx_SharesReleasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_dbx_SharesReleasedDuringPeriodShares_019e2791-2532-7908-b022-9e061470b5a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e2791-2532-788e-96fe-20cdc96767bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e2791-2532-788e-96fe-20cdc96767bf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e2791-2532-786c-8f3c-e96b21a1803e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e2791-2532-786c-8f3c-e96b21a1803e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e2791-2532-77fc-8f0f-858417055706" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e2791-2532-77fc-8f0f-858417055706" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e2791-2532-7d4e-984f-b442de7412c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e2791-2532-7d4e-984f-b442de7412c7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019ea6bc-b798-7cab-80a0-9bea4855fb70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019ea6bc-b798-7cab-80a0-9bea4855fb70" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e2791-2532-7a18-9cd0-4b378fd85cf5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e2791-2532-7a18-9cd0-4b378fd85cf5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e2791-2532-7ba2-8809-2253d668404c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e2791-2532-7ba2-8809-2253d668404c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e2791-2532-75dc-b3b3-39893981c969" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e2791-2532-7741-b802-b5933121fda4" xlink:to="loc_us-gaap_NetIncomeLoss_019e2791-2532-75dc-b3b3-39893981c969" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e2791-2532-7132-803c-37f21686e8b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e2791-2532-7075-816a-8a7ae0d43a2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e2791-2532-7425-8f37-e4a55d97f707" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e2791-2532-7425-8f37-e4a55d97f707" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e2791-2532-7629-994c-17e1d2d7a9bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e2791-2532-7425-8f37-e4a55d97f707" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e2791-2532-7629-994c-17e1d2d7a9bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e2791-2532-7769-bd24-f348e02d30f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e2791-2532-7769-bd24-f348e02d30f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e2791-2532-77f3-9828-5b8695e30ceb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e2791-2532-77f3-9828-5b8695e30ceb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails_1" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesRevenuerecognitionNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e2791-2532-7425-8f37-e4a55d97f707" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e2791-2532-7425-8f37-e4a55d97f707" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e2791-2532-7769-bd24-f348e02d30f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e2791-2532-7769-bd24-f348e02d30f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e2791-2532-77f3-9828-5b8695e30ceb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e2791-2532-7591-b501-c3a698519184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e2791-2532-77f3-9828-5b8695e30ceb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesStockbasedcompensationNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesStockbasedcompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesStockbasedcompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2532-74fb-aad4-0d9462f92299" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2532-712f-8cd5-7f2e19dc0416" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2532-74fb-aad4-0d9462f92299" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2532-712f-8cd5-7f2e19dc0416" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e2791-2532-7ba7-8120-32b793227ed2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2532-712f-8cd5-7f2e19dc0416" xlink:to="loc_us-gaap_AwardTypeAxis_019e2791-2532-7ba7-8120-32b793227ed2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2532-7ba7-8120-32b793227ed2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2532-7ba7-8120-32b793227ed2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2532-7ba7-8120-32b793227ed2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2532-7676-97f9-8e73ea578d96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2532-7ba7-8120-32b793227ed2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2532-7676-97f9-8e73ea578d96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_019e2791-2532-7c80-823e-20b1023c7553" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2532-7676-97f9-8e73ea578d96" xlink:to="loc_us-gaap_RestrictedStockMember_019e2791-2532-7c80-823e-20b1023c7553" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_019e2791-2532-7c57-806e-e6c1040ec9a0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2532-712f-8cd5-7f2e19dc0416" xlink:to="loc_srt_TitleOfIndividualAxis_019e2791-2532-7c57-806e-e6c1040ec9a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2532-7c57-806e-e6c1040ec9a0_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2532-7c57-806e-e6c1040ec9a0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2532-7c57-806e-e6c1040ec9a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2532-7f61-be46-e430d51e325a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2532-7c57-806e-e6c1040ec9a0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2532-7f61-be46-e430d51e325a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ChiefExecutiveOfficerMember_019e2791-2532-74d3-bde7-f856a776d948" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ChiefExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2532-7f61-be46-e430d51e325a" xlink:to="loc_srt_ChiefExecutiveOfficerMember_019e2791-2532-74d3-bde7-f856a776d948" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019e2791-2532-7b02-861d-12f83ccf7343" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2532-712f-8cd5-7f2e19dc0416" xlink:to="loc_us-gaap_PlanNameAxis_019e2791-2532-7b02-861d-12f83ccf7343" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2532-7b02-861d-12f83ccf7343_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2532-7b02-861d-12f83ccf7343" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2532-7b02-861d-12f83ccf7343_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2532-7018-a444-86238802faf9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2532-7b02-861d-12f83ccf7343" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2532-7018-a444-86238802faf9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CoFounderGrantsMember_019e2791-2532-78f3-bc0a-ebe290fbc3f1" xlink:href="dbx-20260630.xsd#dbx_CoFounderGrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019e2791-2532-7018-a444-86238802faf9" xlink:to="loc_dbx_CoFounderGrantsMember_019e2791-2532-78f3-bc0a-ebe290fbc3f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e2791-2532-7b9c-92b0-39ec6d0a3641" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2532-74fb-aad4-0d9462f92299" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e2791-2532-7b9c-92b0-39ec6d0a3641" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2532-784c-9d99-c4559149af12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2532-74fb-aad4-0d9462f92299" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2532-784c-9d99-c4559149af12" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesConcentrationsofriskNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesConcentrationsofriskNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesConcentrationsofriskNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_019e2791-2532-7a3e-936d-ba4fb549a1ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_019e2791-2532-751e-b94f-18c1df2698c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019e2791-2532-7a3e-936d-ba4fb549a1ec" xlink:to="loc_us-gaap_ConcentrationRiskTable_019e2791-2532-751e-b94f-18c1df2698c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e2791-2532-7cda-a33a-d5c042e0cb72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019e2791-2532-751e-b94f-18c1df2698c0" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e2791-2532-7cda-a33a-d5c042e0cb72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e2791-2532-7cda-a33a-d5c042e0cb72_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e2791-2532-7cda-a33a-d5c042e0cb72" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e2791-2532-7cda-a33a-d5c042e0cb72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e2791-2532-7db1-8b27-f1562609349e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e2791-2532-7cda-a33a-d5c042e0cb72" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e2791-2532-7db1-8b27-f1562609349e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_AccountsReceivableAndOtherReceivableMember_019e2791-2532-70d6-aa75-d350b8929192" xlink:href="dbx-20260630.xsd#dbx_AccountsReceivableAndOtherReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e2791-2532-7db1-8b27-f1562609349e" xlink:to="loc_dbx_AccountsReceivableAndOtherReceivableMember_019e2791-2532-70d6-aa75-d350b8929192" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e2791-2532-77f8-9b75-82969795bc9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019e2791-2532-751e-b94f-18c1df2698c0" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e2791-2532-77f8-9b75-82969795bc9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e2791-2532-77f8-9b75-82969795bc9c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e2791-2532-77f8-9b75-82969795bc9c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e2791-2532-77f8-9b75-82969795bc9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e2791-2532-736d-8641-9c5615d299e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e2791-2532-77f8-9b75-82969795bc9c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e2791-2532-736d-8641-9c5615d299e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019e2791-2532-777c-bc71-cf7717e2998f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e2791-2532-736d-8641-9c5615d299e4" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019e2791-2532-777c-bc71-cf7717e2998f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e2791-2532-727b-8083-487dd53a4f28" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019e2791-2532-751e-b94f-18c1df2698c0" xlink:to="loc_srt_MajorCustomersAxis_019e2791-2532-727b-8083-487dd53a4f28" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e2791-2532-727b-8083-487dd53a4f28_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e2791-2532-727b-8083-487dd53a4f28" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e2791-2532-727b-8083-487dd53a4f28_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e2791-2532-7118-98e3-514d8476f85c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e2791-2532-727b-8083-487dd53a4f28" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e2791-2532-7118-98e3-514d8476f85c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_OneDistributionPartnerMember_019fcd16-37cf-7265-aff8-65b3bfda6e89" xlink:href="dbx-20260630.xsd#dbx_OneDistributionPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e2791-2532-7118-98e3-514d8476f85c" xlink:to="loc_dbx_OneDistributionPartnerMember_019fcd16-37cf-7265-aff8-65b3bfda6e89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e2791-2532-7cf0-bf27-d246c67a8f76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019e2791-2532-7a3e-936d-ba4fb549a1ec" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e2791-2532-7cf0-bf27-d246c67a8f76" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-74c2-8b85-db9c9f1d4932_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-74c2-8b85-db9c9f1d4932_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DeferredCommissionsMember_019e2791-2532-7d14-a157-9bdaf870b6f4" xlink:href="dbx-20260630.xsd#dbx_DeferredCommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:to="loc_dbx_DeferredCommissionsMember_019e2791-2532-7d14-a157-9bdaf870b6f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_RenewalCommissionsMember_019e2791-2532-7423-b269-0712ab6411cf" xlink:href="dbx-20260630.xsd#dbx_RenewalCommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:to="loc_dbx_RenewalCommissionsMember_019e2791-2532-7423-b269-0712ab6411cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis_019e2791-2532-7c4e-a26c-cecbb9900897" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfFinancialPositionLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:to="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis_019e2791-2532-7c4e-a26c-cecbb9900897" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CapitalizedContractCostsAdditions_019e2791-2532-776e-af72-20d9f758dca0" xlink:href="dbx-20260630.xsd#dbx_CapitalizedContractCostsAdditions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_dbx_CapitalizedContractCostsAdditions_019e2791-2532-776e-af72-20d9f758dca0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostNet_019e2791-2532-70c3-8452-864c56f52721" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostNet_019e2791-2532-70c3-8452-864c56f52721" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAmortizationPeriod_019e2791-2532-7bc7-994b-e3fba230d829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAmortizationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostAmortizationPeriod_019e2791-2532-7bc7-994b-e3fba230d829" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDeferredSalesCommissions_019e2791-2532-7343-b69c-bd40cb6d359a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfDeferredSalesCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_AmortizationOfDeferredSalesCommissions_019e2791-2532-7343-b69c-bd40cb6d359a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails_1" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesDeferredCommissionsnetNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_019e2791-2532-782d-aa12-b7acfbd621d1" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-74c2-8b85-db9c9f1d4932_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-74c2-8b85-db9c9f1d4932_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_019e2791-2532-74c2-8b85-db9c9f1d4932" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DeferredCommissionsMember_019e2791-2532-7d14-a157-9bdaf870b6f4" xlink:href="dbx-20260630.xsd#dbx_DeferredCommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:to="loc_dbx_DeferredCommissionsMember_019e2791-2532-7d14-a157-9bdaf870b6f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_RenewalCommissionsMember_019e2791-2532-7423-b269-0712ab6411cf" xlink:href="dbx-20260630.xsd#dbx_RenewalCommissionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_019e2791-2532-708e-aa40-660604173f8a" xlink:to="loc_dbx_RenewalCommissionsMember_019e2791-2532-7423-b269-0712ab6411cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CapitalizedContractCostsAdditions_019e2791-2532-776e-af72-20d9f758dca0" xlink:href="dbx-20260630.xsd#dbx_CapitalizedContractCostsAdditions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_dbx_CapitalizedContractCostsAdditions_019e2791-2532-776e-af72-20d9f758dca0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostNet_019e2791-2532-70c3-8452-864c56f52721" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostNet_019e2791-2532-70c3-8452-864c56f52721" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAmortizationPeriod_019e2791-2532-7bc7-994b-e3fba230d829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostAmortizationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_CapitalizedContractCostAmortizationPeriod_019e2791-2532-7bc7-994b-e3fba230d829" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDeferredSalesCommissions_019e2791-2532-7343-b69c-bd40cb6d359a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfDeferredSalesCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_019e2791-2532-7193-a408-a1e27ce90e2b" xlink:to="loc_us-gaap_AmortizationOfDeferredSalesCommissions_019e2791-2532-7343-b69c-bd40cb6d359a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofPropertyandEquipmentDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofPropertyandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DescriptionoftheBusinessandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofPropertyandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7014-82cc-f0015b2fdc77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-7d52-bb0a-587e5c137668" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7014-82cc-f0015b2fdc77" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-7d52-bb0a-587e5c137668" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e2791-2532-7c80-b223-a2ad93dd34b9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-7d52-bb0a-587e5c137668" xlink:to="loc_srt_RangeAxis_019e2791-2532-7c80-b223-a2ad93dd34b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2532-7c80-b223-a2ad93dd34b9_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e2791-2532-7c80-b223-a2ad93dd34b9" xlink:to="loc_srt_RangeMember_019e2791-2532-7c80-b223-a2ad93dd34b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2532-7f76-b363-7e1a64b16da4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e2791-2532-7c80-b223-a2ad93dd34b9" xlink:to="loc_srt_RangeMember_019e2791-2532-7f76-b363-7e1a64b16da4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e2791-2532-74ea-8ab2-66eb4ed580eb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2532-7f76-b363-7e1a64b16da4" xlink:to="loc_srt_MinimumMember_019e2791-2532-74ea-8ab2-66eb4ed580eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e2791-2532-7703-9241-57d5484845ec" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2532-7f76-b363-7e1a64b16da4" xlink:to="loc_srt_MaximumMember_019e2791-2532-7703-9241-57d5484845ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-7bd8-8ec1-29e79e711d2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-7d52-bb0a-587e5c137668" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-7bd8-8ec1-29e79e711d2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7bd8-8ec1-29e79e711d2b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-7bd8-8ec1-29e79e711d2b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7bd8-8ec1-29e79e711d2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7075-843e-c3ec48b3cc9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-7bd8-8ec1-29e79e711d2b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7075-843e-c3ec48b3cc9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_019e2791-2532-7515-afb5-d34732e84c7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7075-843e-c3ec48b3cc9e" xlink:to="loc_us-gaap_ComputerEquipmentMember_019e2791-2532-7515-afb5-d34732e84c7b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_019e2791-2532-72b9-b930-e7aecc319926" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7075-843e-c3ec48b3cc9e" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_019e2791-2532-72b9-b930-e7aecc319926" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019e2791-2532-7ede-b65f-79b2f33ae372" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7014-82cc-f0015b2fdc77" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019e2791-2532-7ede-b65f-79b2f33ae372" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/CashCashEquivalentsandShortTermInvestmentsScheduleofAmortizedCostUnrealizedGainsandLossesandEstimatedFairValueofCashCashEquivalentsandShortTermInvestmentsDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#CashCashEquivalentsandShortTermInvestmentsScheduleofAmortizedCostUnrealizedGainsandLossesandEstimatedFairValueofCashCashEquivalentsandShortTermInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CashCashEquivalentsandShortTermInvestmentsScheduleofAmortizedCostUnrealizedGainsandLossesandEstimatedFairValueofCashCashEquivalentsandShortTermInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e2791-2532-7878-8b8b-9e7fb9911dfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e2791-2532-7878-8b8b-9e7fb9911dfa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-72b1-ae91-1212f8b4be5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e2791-2532-7878-8b8b-9e7fb9911dfa" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-72b1-ae91-1212f8b4be5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-72b1-ae91-1212f8b4be5c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-72b1-ae91-1212f8b4be5c" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-72b1-ae91-1212f8b4be5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-7fd5-9cdb-7d32c4183213" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-72b1-ae91-1212f8b4be5c" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-7fd5-9cdb-7d32c4183213" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashMember_019e2791-2532-707b-9b55-8a2ef827f1bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-7fd5-9cdb-7d32c4183213" xlink:to="loc_us-gaap_CashMember_019e2791-2532-707b-9b55-8a2ef827f1bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_019e2791-2532-750a-9e31-94c6bcd08165" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-7fd5-9cdb-7d32c4183213" xlink:to="loc_us-gaap_MoneyMarketFundsMember_019e2791-2532-750a-9e31-94c6bcd08165" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7ead-933b-b956dc681543" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019e2791-2532-7878-8b8b-9e7fb9911dfa" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7ead-933b-b956dc681543" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ead-933b-b956dc681543_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7ead-933b-b956dc681543" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ead-933b-b956dc681543_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7ead-933b-b956dc681543" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-7576-a660-c8f333c35676" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-7576-a660-c8f333c35676" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-7386-af00-27c88106a8a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-7386-af00-27c88106a8a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_019e2791-2532-71d8-8c88-ccaee152c29e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_us-gaap_MunicipalBondsMember_019e2791-2532-71d8-8c88-ccaee152c29e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-79b0-8408-9bfe73a2da1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-79b0-8408-9bfe73a2da1c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_019e2791-2532-7b13-8fef-f76f23a79dbb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_019e2791-2532-7b13-8fef-f76f23a79dbb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SupranationalSecuritiesMember_019e2791-2532-737e-9996-39f0c5ab5bce" xlink:href="dbx-20260630.xsd#dbx_SupranationalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7ac5-bebb-69e68d4d2590" xlink:to="loc_dbx_SupranationalSecuritiesMember_019e2791-2532-737e-9996-39f0c5ab5bce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e2791-2532-7989-a432-5edd689a2c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e2791-2532-7989-a432-5edd689a2c9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e2791-2532-7300-b581-d2c648900da5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e2791-2532-7300-b581-d2c648900da5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019e2791-2532-7ae4-b6fe-7b83696a7610" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019e2791-2532-7ae4-b6fe-7b83696a7610" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e2791-2532-7305-8a07-2da41755e6e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e2791-2532-7305-8a07-2da41755e6e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e2791-2532-7f76-81d7-f77ec8ff0449" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e2791-2532-7f76-81d7-f77ec8ff0449" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e2791-2532-7606-bbc0-b705880837b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e2791-2532-7606-bbc0-b705880837b1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CashCashEquivalentsAndShortTermInvestmentsAmortizedCost_019e2791-2532-7248-b0a1-fd0e62455760" xlink:href="dbx-20260630.xsd#dbx_CashCashEquivalentsAndShortTermInvestmentsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_dbx_CashCashEquivalentsAndShortTermInvestmentsAmortizedCost_019e2791-2532-7248-b0a1-fd0e62455760" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_019e2791-2532-7da5-9964-96c4f4cfa5cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019e2791-2532-72f8-a340-47fe0d86f019" xlink:to="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_019e2791-2532-7da5-9964-96c4f4cfa5cc" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/CashCashEquivalentsandShortTermInvestmentsScheduleofBreakdownoftheShortTermInvestmentsDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#CashCashEquivalentsandShortTermInvestmentsScheduleofBreakdownoftheShortTermInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/CashCashEquivalentsandShortTermInvestmentsScheduleofBreakdownoftheShortTermInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e2791-2532-7f8b-8c85-0be0877f8e09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_019e2791-2532-75cd-aa1d-2ce4dbecd404" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e2791-2532-7f8b-8c85-0be0877f8e09" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_019e2791-2532-75cd-aa1d-2ce4dbecd404" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7516-9fb7-706cc05ed1d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_019e2791-2532-75cd-aa1d-2ce4dbecd404" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7516-9fb7-706cc05ed1d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7516-9fb7-706cc05ed1d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7516-9fb7-706cc05ed1d1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7516-9fb7-706cc05ed1d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-7516-9fb7-706cc05ed1d1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-7682-8d47-0eefd3be0bb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:to="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-7682-8d47-0eefd3be0bb5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-7d47-a239-64504c83c054" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-7d47-a239-64504c83c054" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_019e2791-2532-7e8c-be4f-1f14dad0ad79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:to="loc_us-gaap_MunicipalBondsMember_019e2791-2532-7e8c-be4f-1f14dad0ad79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-7b51-b6c7-3af34d695837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-70cc-9054-022efb2be3d7" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-7b51-b6c7-3af34d695837" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract_019e2791-2532-7514-9757-1804678a15b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e2791-2532-7f8b-8c85-0be0877f8e09" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract_019e2791-2532-7514-9757-1804678a15b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositionsAbstract_019e2791-2532-7800-b2b8-1884eb655035" xlink:href="dbx-20260630.xsd#dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositionsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract_019e2791-2532-7514-9757-1804678a15b4" xlink:to="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositionsAbstract_019e2791-2532-7800-b2b8-1884eb655035" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e2791-2532-761a-bf7b-08cafdec4344" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositionsAbstract_019e2791-2532-7800-b2b8-1884eb655035" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e2791-2532-761a-bf7b-08cafdec4344" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e2791-2532-7280-a49c-a24d5fa6bee1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositionsAbstract_019e2791-2532-7800-b2b8-1884eb655035" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e2791-2532-7280-a49c-a24d5fa6bee1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositionsAbstract_019e2791-2532-7b19-a93a-15b32bc13590" xlink:href="dbx-20260630.xsd#dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositionsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract_019e2791-2532-7514-9757-1804678a15b4" xlink:to="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositionsAbstract_019e2791-2532-7b19-a93a-15b32bc13590" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e2791-2532-7895-9e40-3fc488dae743" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositionsAbstract_019e2791-2532-7b19-a93a-15b32bc13590" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e2791-2532-7895-9e40-3fc488dae743" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e2791-2532-7961-9ff2-5694d50e551c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositionsAbstract_019e2791-2532-7b19-a93a-15b32bc13590" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e2791-2532-7961-9ff2-5694d50e551c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e2791-2532-7b05-8ad6-da14edb4c517" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleGainLossAbstract_019e2791-2532-7514-9757-1804678a15b4" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e2791-2532-7b05-8ad6-da14edb4c517" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e2791-2532-7f3d-aedf-84d8c26b86a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e2791-2532-7b05-8ad6-da14edb4c517" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e2791-2532-7f3d-aedf-84d8c26b86a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e2791-2532-746d-86f7-6e815a7f7ba6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e2791-2532-7b05-8ad6-da14edb4c517" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e2791-2532-746d-86f7-6e815a7f7ba6" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/FairValueMeasurementsScheduleofFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7a72-9146-e57a76ca6f87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-75ba-bdc5-e6de0ccc9383" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7a72-9146-e57a76ca6f87" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-75ba-bdc5-e6de0ccc9383" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-79d3-90c3-e85ccc1fd279" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-75ba-bdc5-e6de0ccc9383" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-79d3-90c3-e85ccc1fd279" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-79d3-90c3-e85ccc1fd279_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-79d3-90c3-e85ccc1fd279" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-79d3-90c3-e85ccc1fd279_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-73ce-8d8c-a36900669442" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e2791-2532-79d3-90c3-e85ccc1fd279" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-73ce-8d8c-a36900669442" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_019e2791-2532-7956-8b60-f2f626e8ac03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e2791-2532-73ce-8d8c-a36900669442" xlink:to="loc_us-gaap_MoneyMarketFundsMember_019e2791-2532-7956-8b60-f2f626e8ac03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7227-9c48-b2d99876a87f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-75ba-bdc5-e6de0ccc9383" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7227-9c48-b2d99876a87f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7227-9c48-b2d99876a87f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7227-9c48-b2d99876a87f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7227-9c48-b2d99876a87f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7173-951b-261e443d7382" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7227-9c48-b2d99876a87f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7173-951b-261e443d7382" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e2791-2532-753b-ac3f-d17e72a3ce48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7173-951b-261e443d7382" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e2791-2532-753b-ac3f-d17e72a3ce48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e2791-2532-743f-a7f8-3ae232448290" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7173-951b-261e443d7382" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e2791-2532-743f-a7f8-3ae232448290" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e2791-2532-76e4-ba8f-41965fc37d8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7173-951b-261e443d7382" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e2791-2532-76e4-ba8f-41965fc37d8e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-74e6-8fea-2f2d7af5bec0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-75ba-bdc5-e6de0ccc9383" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-74e6-8fea-2f2d7af5bec0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-74e6-8fea-2f2d7af5bec0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-74e6-8fea-2f2d7af5bec0" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-74e6-8fea-2f2d7af5bec0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e2791-2532-74e6-8fea-2f2d7af5bec0" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-75e3-8762-24be3acacc11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_us-gaap_CorporateNoteSecuritiesMember_019e2791-2532-75e3-8762-24be3acacc11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-799d-8fe3-32da545145d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019e2791-2532-799d-8fe3-32da545145d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_019e2791-2532-70d1-9cfc-27a6ab01fe07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_us-gaap_MunicipalBondsMember_019e2791-2532-70d1-9cfc-27a6ab01fe07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-7b04-813f-6b8ac627d4d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019e2791-2532-7b04-813f-6b8ac627d4d8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_019e2791-2532-721e-b993-ab35e36d07fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_019e2791-2532-721e-b993-ab35e36d07fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SupranationalSecuritiesMember_019e2791-2532-7f70-bf19-767ff31b402f" xlink:href="dbx-20260630.xsd#dbx_SupranationalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e2791-2532-7e66-8d15-58fbf15e32a6" xlink:to="loc_dbx_SupranationalSecuritiesMember_019e2791-2532-7f70-bf19-767ff31b402f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CashEquivalentsFairValueDisclosure_019e2791-2532-78d7-a111-3bde6db8f46c" xlink:href="dbx-20260630.xsd#dbx_CashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7a72-9146-e57a76ca6f87" xlink:to="loc_dbx_CashEquivalentsFairValueDisclosure_019e2791-2532-78d7-a111-3bde6db8f46c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e2791-2532-74d5-b950-4c359f539e00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7a72-9146-e57a76ca6f87" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e2791-2532-74d5-b950-4c359f539e00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e2791-2532-71a6-b5b5-d5a2fd82d4f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7a72-9146-e57a76ca6f87" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e2791-2532-71a6-b5b5-d5a2fd82d4f5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#FairValueMeasurementsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2532-70a5-b74a-bb5a1c9ac3de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2532-70a5-b74a-bb5a1c9ac3de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-70a5-b74a-bb5a1c9ac3de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2532-70a5-b74a-bb5a1c9ac3de" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-70a5-b74a-bb5a1c9ac3de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-759f-a5c0-ea7d776859c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2532-70a5-b74a-bb5a1c9ac3de" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-759f-a5c0-ea7d776859c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028ConvertibleNotesMember_019e2791-2532-7ff1-8ef3-5f9a88e6cfef" xlink:href="dbx-20260630.xsd#dbx_A2028ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-759f-a5c0-ea7d776859c7" xlink:to="loc_dbx_A2028ConvertibleNotesMember_019e2791-2532-7ff1-8ef3-5f9a88e6cfef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019e2791-2532-7e39-90c8-cb46c54d64e1" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2532-759f-a5c0-ea7d776859c7" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019e2791-2532-7e39-90c8-cb46c54d64e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2532-734e-aa8c-7c044e4db3ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2532-734e-aa8c-7c044e4db3ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-734e-aa8c-7c044e4db3ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2532-734e-aa8c-7c044e4db3ae" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-734e-aa8c-7c044e4db3ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-7ccb-8e19-d13d402efb40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2532-734e-aa8c-7c044e4db3ae" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-7ccb-8e19-d13d402efb40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2532-704a-b722-686c88d163a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-7ccb-8e19-d13d402efb40" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2532-704a-b722-686c88d163a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2532-78b7-af87-c1e10667c1df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2532-7ccb-8e19-d13d402efb40" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2532-78b7-af87-c1e10667c1df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7013-9a80-a37075ee9cb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7013-9a80-a37075ee9cb7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7013-9a80-a37075ee9cb7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7013-9a80-a37075ee9cb7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7013-9a80-a37075ee9cb7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7fd0-bea0-108a2c13bbb9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e2791-2532-7013-9a80-a37075ee9cb7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7fd0-bea0-108a2c13bbb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e2791-2532-7a48-9cd3-4941968c7b69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e2791-2532-7fd0-bea0-108a2c13bbb9" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e2791-2532-7a48-9cd3-4941968c7b69" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e2791-2532-744d-a70d-6ea5c27bd157" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e2791-2532-7555-8661-549ce3f53d17" xlink:to="loc_us-gaap_CreditFacilityAxis_019e2791-2532-744d-a70d-6ea5c27bd157" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2532-744d-a70d-6ea5c27bd157_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2532-744d-a70d-6ea5c27bd157" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2532-744d-a70d-6ea5c27bd157_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2532-7fdc-b0a4-16ba8924cb45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2532-744d-a70d-6ea5c27bd157" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2532-7fdc-b0a4-16ba8924cb45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e2791-2532-7d89-96e4-b3e86c3442dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2532-7fdc-b0a4-16ba8924cb45" xlink:to="loc_us-gaap_SecuredDebtMember_019e2791-2532-7d89-96e4-b3e86c3442dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019e2791-2532-7f8c-9221-af4e7c4ada6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019e2791-2532-7f8c-9221-af4e7c4ada6c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e2791-2532-7840-b0c0-401f0a831b1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e2791-2532-7840-b0c0-401f0a831b1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtFairValueDisclosures_019e2791-2532-7999-8124-3f526e683f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtFairValueDisclosures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_ConvertibleDebtFairValueDisclosures_019e2791-2532-7999-8124-3f526e683f7b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2532-7f4f-a59d-6d620ac82215" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2532-7f4f-a59d-6d620ac82215" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e2791-2532-7d1c-88df-8cd615fa639c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e2791-2532-7c18-b81f-d8fe07c334fc" xlink:to="loc_us-gaap_LongTermDebt_019e2791-2532-7d1c-88df-8cd615fa639c" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/PropertyandEquipmentNetScheduleofPropertyandEquipmentNetDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#PropertyandEquipmentNetScheduleofPropertyandEquipmentNetDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/PropertyandEquipmentNetScheduleofPropertyandEquipmentNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7c69-9dbe-49a2addb356d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-710f-9312-581489ede293" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7c69-9dbe-49a2addb356d" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-710f-9312-581489ede293" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-72bd-9ef3-1ff93643aa16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019e2791-2532-710f-9312-581489ede293" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-72bd-9ef3-1ff93643aa16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-72bd-9ef3-1ff93643aa16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-72bd-9ef3-1ff93643aa16" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-72bd-9ef3-1ff93643aa16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e2791-2532-72bd-9ef3-1ff93643aa16" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_019e2791-2532-7eb4-889b-e4ce5fb4c1f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:to="loc_us-gaap_ComputerEquipmentMember_019e2791-2532-7eb4-889b-e4ce5fb4c1f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_019e2791-2532-7db2-a414-0ec5d3c0611b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_019e2791-2532-7db2-a414-0ec5d3c0611b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_019e2791-2532-7ec3-9842-1d10cb9ff99c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_019e2791-2532-7ec3-9842-1d10cb9ff99c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_019e2791-2532-7e4f-b2b1-49a795a5ed63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e2791-2532-7fd1-b839-018e36f0bb26" xlink:to="loc_us-gaap_ConstructionInProgressMember_019e2791-2532-7e4f-b2b1-49a795a5ed63" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019e2791-2532-73c2-aaa0-e8ce430424bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7c69-9dbe-49a2addb356d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019e2791-2532-73c2-aaa0-e8ce430424bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e2791-2532-7326-9ffa-3b4f9c0d5f4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7c69-9dbe-49a2addb356d" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e2791-2532-7326-9ffa-3b4f9c0d5f4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e2791-2532-74c5-a0a1-400d335085cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019e2791-2532-7c69-9dbe-49a2addb356d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e2791-2532-74c5-a0a1-400d335085cf" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/IntangibleAssetsScheduleofIntangibleAssetsDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#IntangibleAssetsScheduleofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/IntangibleAssetsScheduleofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019e2791-2532-71ae-9047-92b371a2faed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019e2791-2532-71ae-9047-92b371a2faed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e2791-2532-7e8f-a78d-149d56200a08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019e2791-2532-71ae-9047-92b371a2faed" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e2791-2532-7e8f-a78d-149d56200a08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7e8f-a78d-149d56200a08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e2791-2532-7e8f-a78d-149d56200a08" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7e8f-a78d-149d56200a08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e2791-2532-7e8f-a78d-149d56200a08" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_019e2791-2532-75e8-866f-1a09e5da152e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_019e2791-2532-75e8-866f-1a09e5da152e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019e2791-2532-7a06-8ef5-37c44438a6b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019e2791-2532-7a06-8ef5-37c44438a6b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PatentsMember_019e2791-2532-7781-a4e1-348e5d01bcc5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PatentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_PatentsMember_019e2791-2532-7781-a4e1-348e5d01bcc5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_019e279d-1623-7558-a18c-4eaf98fd5b7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_019e279d-1623-7558-a18c-4eaf98fd5b7f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_019e2791-2532-7ef6-9bb7-15a09b097dba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_019e2791-2532-7ef6-9bb7-15a09b097dba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_019e2791-2532-7509-b18c-68b64d9024ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_LicensingAgreementsMember_019e2791-2532-7509-b18c-68b64d9024ea" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_AssembledWorkforceInAssetAcquisitionMember_019e2791-2532-79ba-9441-8b83ca648ad5" xlink:href="dbx-20260630.xsd#dbx_AssembledWorkforceInAssetAcquisitionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_dbx_AssembledWorkforceInAssetAcquisitionMember_019e2791-2532-79ba-9441-8b83ca648ad5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019e2791-2532-7b97-bf49-76b922160901" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e2791-2532-7a81-8ee0-93926bbd71af" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019e2791-2532-7b97-bf49-76b922160901" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e2791-2532-70dd-b840-d49c8dc0917c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019e2791-2532-71ae-9047-92b371a2faed" xlink:to="loc_srt_RangeAxis_019e2791-2532-70dd-b840-d49c8dc0917c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2532-70dd-b840-d49c8dc0917c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e2791-2532-70dd-b840-d49c8dc0917c" xlink:to="loc_srt_RangeMember_019e2791-2532-70dd-b840-d49c8dc0917c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2532-708a-b8f6-5f4ab5d96d21" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e2791-2532-70dd-b840-d49c8dc0917c" xlink:to="loc_srt_RangeMember_019e2791-2532-708a-b8f6-5f4ab5d96d21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_019e2791-2532-7a41-ae58-8cd70298f522" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2532-708a-b8f6-5f4ab5d96d21" xlink:to="loc_srt_WeightedAverageMember_019e2791-2532-7a41-ae58-8cd70298f522" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019e2791-2532-7727-9e1e-fd5cc217ff7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_019e2791-2532-7727-9e1e-fd5cc217ff7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e2791-2532-7fe4-a2be-6aa612d1b96a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e2791-2532-7fe4-a2be-6aa612d1b96a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019e2791-2532-797f-a076-e63b4e49ac66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019e2791-2532-797f-a076-e63b4e49ac66" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e2791-2532-7aa1-8f3f-e70494debe57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e2791-2532-7890-a0d4-09584113abd7" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e2791-2532-7aa1-8f3f-e70494debe57" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtRevolvingcreditfacilityNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtRevolvingcreditfacilityNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtRevolvingcreditfacilityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e2791-2605-78eb-b154-568951428bbe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_us-gaap_CreditFacilityAxis_019e2791-2605-78eb-b154-568951428bbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-78eb-b154-568951428bbe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-78eb-b154-568951428bbe" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-78eb-b154-568951428bbe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-76e9-93c2-7fd0628881bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-78eb-b154-568951428bbe" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-76e9-93c2-7fd0628881bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_019e2791-2605-7b0b-8fbc-f93b9861bdcb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2605-76e9-93c2-7fd0628881bd" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_019e2791-2605-7b0b-8fbc-f93b9861bdcb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_019e2791-2605-72cb-9998-e323bc99ee15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2605-76e9-93c2-7fd0628881bd" xlink:to="loc_us-gaap_LetterOfCreditMember_019e2791-2605-72cb-9998-e323bc99ee15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019fc756-ce28-76b0-848c-f0b628079b1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2605-76e9-93c2-7fd0628881bd" xlink:to="loc_us-gaap_SecuredDebtMember_019fc756-ce28-76b0-848c-f0b628079b1e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-715e-a9c4-7b952660127b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-715e-a9c4-7b952660127b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-715e-a9c4-7b952660127b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-715e-a9c4-7b952660127b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-715e-a9c4-7b952660127b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7313-9663-788edfe21221" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-715e-a9c4-7b952660127b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7313-9663-788edfe21221" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026RevolvingCreditAgreementMember_019f7f66-3a51-7fbe-8b45-62daa07652d8" xlink:href="dbx-20260630.xsd#dbx_A2026RevolvingCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7313-9663-788edfe21221" xlink:to="loc_dbx_A2026RevolvingCreditAgreementMember_019f7f66-3a51-7fbe-8b45-62daa07652d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-769b-a3ba-9aa508ea07a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-769b-a3ba-9aa508ea07a9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-769b-a3ba-9aa508ea07a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-769b-a3ba-9aa508ea07a9" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-769b-a3ba-9aa508ea07a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7621-a84a-01fbe5dd3580" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-769b-a3ba-9aa508ea07a9" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7621-a84a-01fbe5dd3580" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2605-7e4d-a3e7-748dc699a5f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7621-a84a-01fbe5dd3580" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2605-7e4d-a3e7-748dc699a5f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentAxis_019fa905-6f04-735e-9656-fe70789ea3be" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_dbx_VariableRateComponentAxis_019fa905-6f04-735e-9656-fe70789ea3be" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentDomain_019fa905-6f04-735e-9656-fe70789ea3be_default" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dbx_VariableRateComponentAxis_019fa905-6f04-735e-9656-fe70789ea3be" xlink:to="loc_dbx_VariableRateComponentDomain_019fa905-6f04-735e-9656-fe70789ea3be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentDomain_019fa905-6f04-70e9-b28d-af982e04ce84" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dbx_VariableRateComponentAxis_019fa905-6f04-735e-9656-fe70789ea3be" xlink:to="loc_dbx_VariableRateComponentDomain_019fa905-6f04-70e9-b28d-af982e04ce84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentOneMember_019fa905-a66f-7024-8230-95a71061fe1e" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_VariableRateComponentDomain_019fa905-6f04-70e9-b28d-af982e04ce84" xlink:to="loc_dbx_VariableRateComponentOneMember_019fa905-a66f-7024-8230-95a71061fe1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentTwoMember_019fa906-603e-72bc-ba16-19ecb448b52b" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_VariableRateComponentDomain_019fa905-6f04-70e9-b28d-af982e04ce84" xlink:to="loc_dbx_VariableRateComponentTwoMember_019fa906-603e-72bc-ba16-19ecb448b52b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019e2791-2605-7d0c-932d-fbe651a4bc9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_us-gaap_VariableRateAxis_019e2791-2605-7d0c-932d-fbe651a4bc9b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e2791-2605-7d0c-932d-fbe651a4bc9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019e2791-2605-7d0c-932d-fbe651a4bc9b" xlink:to="loc_us-gaap_VariableRateDomain_019e2791-2605-7d0c-932d-fbe651a4bc9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e2791-2605-74a4-aeff-d7bd2ceb53f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019e2791-2605-7d0c-932d-fbe651a4bc9b" xlink:to="loc_us-gaap_VariableRateDomain_019e2791-2605-74a4-aeff-d7bd2ceb53f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_FederalFundsRateMember_019fc756-ce28-721f-a183-3bb65ee4d8b5" xlink:href="dbx-20260630.xsd#dbx_FederalFundsRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e2791-2605-74a4-aeff-d7bd2ceb53f9" xlink:to="loc_dbx_FederalFundsRateMember_019fc756-ce28-721f-a183-3bb65ee4d8b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsEffectiveSwapRateMember_019fcd1a-1052-7239-8df8-3492fe10f95f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalFundsEffectiveSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e2791-2605-74a4-aeff-d7bd2ceb53f9" xlink:to="loc_us-gaap_FederalFundsEffectiveSwapRateMember_019fcd1a-1052-7239-8df8-3492fe10f95f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019e2791-2605-7eab-ae52-b31f074e47e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e2791-2605-74a4-aeff-d7bd2ceb53f9" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019e2791-2605-7eab-ae52-b31f074e47e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa904-a6bf-7dc4-9f63-0a13426727cb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2605-75ce-a4d3-aadb77600f2a" xlink:to="loc_srt_RangeAxis_019fa904-a6bf-7dc4-9f63-0a13426727cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa904-a6bf-7dc4-9f63-0a13426727cb_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa904-a6bf-7dc4-9f63-0a13426727cb" xlink:to="loc_srt_RangeMember_019fa904-a6bf-7dc4-9f63-0a13426727cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa904-a6bf-71b4-9dc4-728194f6acf5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa904-a6bf-7dc4-9f63-0a13426727cb" xlink:to="loc_srt_RangeMember_019fa904-a6bf-71b4-9dc4-728194f6acf5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019fa904-cb06-7255-8702-ac16e2df7927" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa904-a6bf-71b4-9dc4-728194f6acf5" xlink:to="loc_srt_MinimumMember_019fa904-cb06-7255-8702-ac16e2df7927" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019fa904-f25a-7604-b1d1-1faba264ac93" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa904-a6bf-71b4-9dc4-728194f6acf5" xlink:to="loc_srt_MaximumMember_019fa904-f25a-7604-b1d1-1faba264ac93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2605-7835-8ed1-de4d5928887b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2605-7835-8ed1-de4d5928887b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019fa8fd-b360-7713-aa17-c45e67df3cb3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019fa8fd-b360-7713-aa17-c45e67df3cb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_019f8083-51aa-7613-943a-9f429e1a92cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_019f8083-51aa-7613-943a-9f429e1a92cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e2791-2605-772d-a01c-3dfd28ce3f85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e2791-2605-772d-a01c-3dfd28ce3f85" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019fa908-775f-7dd3-acf3-b9139b688def" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019fa908-775f-7dd3-acf3-b9139b688def" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019f7fa6-597c-7408-878c-9ea0489f18f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2605-7aa0-9371-450529091523" xlink:to="loc_us-gaap_InterestExpenseDebt_019f7fa6-597c-7408-878c-9ea0489f18f3" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtTermLoanFacilityNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtTermLoanFacilityNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtTermLoanFacilityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e2791-2533-719d-9ea8-baf9519bd945" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_us-gaap_CreditFacilityAxis_019e2791-2533-719d-9ea8-baf9519bd945" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2533-719d-9ea8-baf9519bd945_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2533-719d-9ea8-baf9519bd945" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2533-719d-9ea8-baf9519bd945_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2533-757e-b9d3-3bb0d34e53ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2533-719d-9ea8-baf9519bd945" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2533-757e-b9d3-3bb0d34e53ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e2791-2533-7b44-8a2c-a971d2361b62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2533-757e-b9d3-3bb0d34e53ae" xlink:to="loc_us-gaap_SecuredDebtMember_019e2791-2533-7b44-8a2c-a971d2361b62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_019e2791-2533-7946-a240-2970208b378e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2533-757e-b9d3-3bb0d34e53ae" xlink:to="loc_us-gaap_LetterOfCreditMember_019e2791-2533-7946-a240-2970208b378e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2533-7d73-bba2-86a0b07b742e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2533-7d73-bba2-86a0b07b742e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7d73-bba2-86a0b07b742e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2533-7d73-bba2-86a0b07b742e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7d73-bba2-86a0b07b742e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7809-8348-097c32edbb8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2533-7d73-bba2-86a0b07b742e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7809-8348-097c32edbb8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019e2791-2533-727b-8790-e4bf8e4ece9d" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7809-8348-097c32edbb8a" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019e2791-2533-727b-8790-e4bf8e4ece9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CreditAgreementInitialTermLoanMember_019e2791-2533-7a89-b1eb-3cb8c7ece39c" xlink:href="dbx-20260630.xsd#dbx_CreditAgreementInitialTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_TermLoanCreditAgreementMember_019e2791-2533-727b-8790-e4bf8e4ece9d" xlink:to="loc_dbx_CreditAgreementInitialTermLoanMember_019e2791-2533-7a89-b1eb-3cb8c7ece39c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CreditAgreementDelayedDrawTermLoanMember_019e2791-2533-7dff-be9a-7a4124020258" xlink:href="dbx-20260630.xsd#dbx_CreditAgreementDelayedDrawTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_TermLoanCreditAgreementMember_019e2791-2533-727b-8790-e4bf8e4ece9d" xlink:to="loc_dbx_CreditAgreementDelayedDrawTermLoanMember_019e2791-2533-7dff-be9a-7a4124020258" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CreditAgreement2025DelayedDrawTermLoanMember_019e2791-2533-74d1-96f4-3a759402c535" xlink:href="dbx-20260630.xsd#dbx_CreditAgreement2025DelayedDrawTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2533-7809-8348-097c32edbb8a" xlink:to="loc_dbx_CreditAgreement2025DelayedDrawTermLoanMember_019e2791-2533-74d1-96f4-3a759402c535" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2533-789a-aa7b-f52ae2f2e45e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2533-789a-aa7b-f52ae2f2e45e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2533-789a-aa7b-f52ae2f2e45e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2533-789a-aa7b-f52ae2f2e45e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2533-789a-aa7b-f52ae2f2e45e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2533-74d4-b566-d78be83d469f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2533-789a-aa7b-f52ae2f2e45e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2533-74d4-b566-d78be83d469f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2533-7c34-8c3f-81af0feebcff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2533-74d4-b566-d78be83d469f" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2533-7c34-8c3f-81af0feebcff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019e2791-2533-73e7-b4b3-4382e73fea79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019e2791-2533-73e7-b4b3-4382e73fea79" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-73e7-b4b3-4382e73fea79_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019e2791-2533-73e7-b4b3-4382e73fea79" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-73e7-b4b3-4382e73fea79_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-77b3-9ba8-c72a844148fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_019e2791-2533-73e7-b4b3-4382e73fea79" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-77b3-9ba8-c72a844148fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_019e2791-2533-7056-bf5c-888457bd0f61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-77b3-9ba8-c72a844148fc" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_019e2791-2533-7056-bf5c-888457bd0f61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_019e2791-2533-789f-8b73-1ef64056ea5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_019e2791-2533-77b3-9ba8-c72a844148fc" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_019e2791-2533-789f-8b73-1ef64056ea5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentAxis_019e2791-2533-7238-b0d0-3f055b587403" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_dbx_VariableRateComponentAxis_019e2791-2533-7238-b0d0-3f055b587403" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentDomain_019e2791-2533-7238-b0d0-3f055b587403_default" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dbx_VariableRateComponentAxis_019e2791-2533-7238-b0d0-3f055b587403" xlink:to="loc_dbx_VariableRateComponentDomain_019e2791-2533-7238-b0d0-3f055b587403_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentDomain_019e2791-2533-7f34-a884-7e7caaf24c25" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dbx_VariableRateComponentAxis_019e2791-2533-7238-b0d0-3f055b587403" xlink:to="loc_dbx_VariableRateComponentDomain_019e2791-2533-7f34-a884-7e7caaf24c25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentOneMember_019e2791-2533-7163-88dd-49b8f5a6f1f4" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_VariableRateComponentDomain_019e2791-2533-7f34-a884-7e7caaf24c25" xlink:to="loc_dbx_VariableRateComponentOneMember_019e2791-2533-7163-88dd-49b8f5a6f1f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_VariableRateComponentTwoMember_019e2791-2533-753f-a6f8-248cc1a1f769" xlink:href="dbx-20260630.xsd#dbx_VariableRateComponentTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_VariableRateComponentDomain_019e2791-2533-7f34-a884-7e7caaf24c25" xlink:to="loc_dbx_VariableRateComponentTwoMember_019e2791-2533-753f-a6f8-248cc1a1f769" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019e2791-2533-7763-b967-47e5c9cf2cd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e2791-2533-7726-b6a0-c9d23ff24425" xlink:to="loc_us-gaap_VariableRateAxis_019e2791-2533-7763-b967-47e5c9cf2cd8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e2791-2533-7763-b967-47e5c9cf2cd8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019e2791-2533-7763-b967-47e5c9cf2cd8" xlink:to="loc_us-gaap_VariableRateDomain_019e2791-2533-7763-b967-47e5c9cf2cd8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019e2791-2533-7ec6-808a-36331996fc00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019e2791-2533-7763-b967-47e5c9cf2cd8" xlink:to="loc_us-gaap_VariableRateDomain_019e2791-2533-7ec6-808a-36331996fc00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_FederalFundsRateMember_019e2791-2533-7bbb-baea-7a98c23c174d" xlink:href="dbx-20260630.xsd#dbx_FederalFundsRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e2791-2533-7ec6-808a-36331996fc00" xlink:to="loc_dbx_FederalFundsRateMember_019e2791-2533-7bbb-baea-7a98c23c174d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019e2791-2533-7ae6-b275-aec900688684" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019e2791-2533-7ec6-808a-36331996fc00" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019e2791-2533-7ae6-b275-aec900688684" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019e2791-2533-7daf-b0fb-d2b9937f793f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_DebtInstrumentTerm_019e2791-2533-7daf-b0fb-d2b9937f793f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2533-792d-b540-d895f04b638d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2533-792d-b540-d895f04b638d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_019e2791-2533-76f4-8031-da8be7048d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_019e2791-2533-76f4-8031-da8be7048d0a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2533-7598-8704-9d64c044aa80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2533-7598-8704-9d64c044aa80" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e2791-2533-7300-886a-66419365b35a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019e2791-2533-7300-886a-66419365b35a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e2791-2533-7f05-abbd-58d1cf04a6f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_019e2791-2533-7f05-abbd-58d1cf04a6f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_019e2791-2533-76d3-8d90-43e335314802" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_019e2791-2533-76d3-8d90-43e335314802" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_019e2791-2533-73de-bbad-c2db5b76f578" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromLinesOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_019e2791-2533-73de-bbad-c2db5b76f578" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e2791-2533-7e5d-b12d-98f6feef0003" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019e2791-2533-7e5d-b12d-98f6feef0003" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LineOfCreditFacilityCommitmentFeeDeferredIssuanceCostsReclassified_019e2791-2533-7399-8611-4a3bf3078e0a" xlink:href="dbx-20260630.xsd#dbx_LineOfCreditFacilityCommitmentFeeDeferredIssuanceCostsReclassified"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_dbx_LineOfCreditFacilityCommitmentFeeDeferredIssuanceCostsReclassified_019e2791-2533-7399-8611-4a3bf3078e0a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtInstrumentPeriodicPaymentQuarterlyPercentageOfPrincipal_019e2791-2605-7adf-8144-9c9ece852479" xlink:href="dbx-20260630.xsd#dbx_DebtInstrumentPeriodicPaymentQuarterlyPercentageOfPrincipal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_dbx_DebtInstrumentPeriodicPaymentQuarterlyPercentageOfPrincipal_019e2791-2605-7adf-8144-9c9ece852479" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtInstrumentPrepaymentPremiumPercent_019e2791-2605-7072-abb8-04b69cb7c0e1" xlink:href="dbx-20260630.xsd#dbx_DebtInstrumentPrepaymentPremiumPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_dbx_DebtInstrumentPrepaymentPremiumPercent_019e2791-2605-7072-abb8-04b69cb7c0e1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e2791-2605-7a09-8469-1707fe8aa510" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e2791-2605-7a09-8469-1707fe8aa510" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019e2791-2605-70e7-a81e-ff7d7d188c49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e2791-2533-7a79-aac1-cee6fb8eedbe" xlink:to="loc_us-gaap_InterestExpenseDebt_019e2791-2605-70e7-a81e-ff7d7d188c49" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtScheduleofTermLoanFacilityDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtScheduleofTermLoanFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtScheduleofTermLoanFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7747-abfa-4d928879e545" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7758-9d61-6d4a02f02b77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7747-abfa-4d928879e545" xlink:to="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7758-9d61-6d4a02f02b77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7bad-a9f7-3296665e85ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7758-9d61-6d4a02f02b77" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7bad-a9f7-3296665e85ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7bad-a9f7-3296665e85ec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7bad-a9f7-3296665e85ec" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7bad-a9f7-3296665e85ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c86-bea2-74914a4b8c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7bad-a9f7-3296665e85ec" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c86-bea2-74914a4b8c8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2605-7add-9d64-99a095c034f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c86-bea2-74914a4b8c8b" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2605-7add-9d64-99a095c034f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7b2a-b535-a51837b98e03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7758-9d61-6d4a02f02b77" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7b2a-b535-a51837b98e03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7b2a-b535-a51837b98e03_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7b2a-b535-a51837b98e03" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7b2a-b535-a51837b98e03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7aca-9453-a5344fc7e1bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7b2a-b535-a51837b98e03" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7aca-9453-a5344fc7e1bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019e2791-2605-72b8-a8fa-f21c6f95aca8" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7aca-9453-a5344fc7e1bb" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019e2791-2605-72b8-a8fa-f21c6f95aca8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-700f-95fd-c824799c9ef6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7747-abfa-4d928879e545" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-700f-95fd-c824799c9ef6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_019e2791-2605-7f55-8f88-d837c61d51e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnamortizedDebtIssuanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7747-abfa-4d928879e545" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_019e2791-2605-7f55-8f88-d837c61d51e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e2791-2605-7084-92a3-c0d4494f79b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7747-abfa-4d928879e545" xlink:to="loc_us-gaap_LongTermDebt_019e2791-2605-7084-92a3-c0d4494f79b5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtScheduleofTermLoanDebtDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtScheduleofTermLoanDebtDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtScheduleofTermLoanDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c97-9aec-8b2bccf910c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c97-9aec-8b2bccf910c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7fa1-92ff-f904692b2931" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c97-9aec-8b2bccf910c0" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7fa1-92ff-f904692b2931" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7fa1-92ff-f904692b2931_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7fa1-92ff-f904692b2931" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7fa1-92ff-f904692b2931_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bc5-875d-bccb6b1f498a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7fa1-92ff-f904692b2931" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bc5-875d-bccb6b1f498a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019e2791-2605-73c0-beb9-534a0a9db1db" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bc5-875d-bccb6b1f498a" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019e2791-2605-73c0-beb9-534a0a9db1db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7712-9328-f4c7825bdf6f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c97-9aec-8b2bccf910c0" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7712-9328-f4c7825bdf6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7712-9328-f4c7825bdf6f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7712-9328-f4c7825bdf6f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7712-9328-f4c7825bdf6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7763-be57-37377ad26963" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7712-9328-f4c7825bdf6f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7763-be57-37377ad26963" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2605-7535-b0a7-2c978dad5b29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7763-be57-37377ad26963" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2605-7535-b0a7-2c978dad5b29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-71fb-b50f-7bebd29b6ad2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7763-be57-37377ad26963" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-71fb-b50f-7bebd29b6ad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e2791-2605-79d5-a428-ed11ad76c4fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c97-9aec-8b2bccf910c0" xlink:to="loc_us-gaap_CreditFacilityAxis_019e2791-2605-79d5-a428-ed11ad76c4fb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-79d5-a428-ed11ad76c4fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-79d5-a428-ed11ad76c4fb" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-79d5-a428-ed11ad76c4fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7995-86a7-7b127a5bd5c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-79d5-a428-ed11ad76c4fb" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7995-86a7-7b127a5bd5c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e2791-2605-7c54-9356-c6879f89c0d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7995-86a7-7b127a5bd5c1" xlink:to="loc_us-gaap_SecuredDebtMember_019e2791-2605-7c54-9356-c6879f89c0d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e2791-2605-7a03-899c-b425e9c9b431" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e2791-2605-7a03-899c-b425e9c9b431" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e2791-2605-76b3-87b1-cea9bf0b0fb9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e2791-2605-76b3-87b1-cea9bf0b0fb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e2791-2605-70a2-867b-428076566d5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e2791-2605-70a2-867b-428076566d5b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e2791-2605-70a8-ae2d-2bfe8de6d9e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e2791-2605-70a8-ae2d-2bfe8de6d9e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LongTermDebtMaturityYearFourAndAfter_019f9464-0375-711c-9a24-5ae5330d2ebd" xlink:href="dbx-20260630.xsd#dbx_LongTermDebtMaturityYearFourAndAfter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_dbx_LongTermDebtMaturityYearFourAndAfter_019f9464-0375-711c-9a24-5ae5330d2ebd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7a55-9f18-b9392e2e2c38" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7240-87ce-d422fa49f40a" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7a55-9f18-b9392e2e2c38" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtConvertibleSeniorNotesNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtConvertibleSeniorNotesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtConvertibleSeniorNotesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-752a-8d21-183c2c15ccc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-752a-8d21-183c2c15ccc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-752a-8d21-183c2c15ccc3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-752a-8d21-183c2c15ccc3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-752a-8d21-183c2c15ccc3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-72a5-9487-83db391461cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-752a-8d21-183c2c15ccc3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-72a5-9487-83db391461cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-7bd9-9a24-4ee6a3a4530d" xlink:href="dbx-20260630.xsd#dbx_A2026ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-72a5-9487-83db391461cb" xlink:to="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-7bd9-9a24-4ee6a3a4530d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-71f1-a548-94ffc4d5cf27" xlink:href="dbx-20260630.xsd#dbx_A2028ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-72a5-9487-83db391461cb" xlink:to="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-71f1-a548-94ffc4d5cf27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7305-8e0e-c5c2817fe4df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7305-8e0e-c5c2817fe4df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7305-8e0e-c5c2817fe4df_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7305-8e0e-c5c2817fe4df" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7305-8e0e-c5c2817fe4df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7ab3-b583-ccc43c3b98bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7305-8e0e-c5c2817fe4df" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7ab3-b583-ccc43c3b98bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7fe3-8255-407646c34172" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7ab3-b583-ccc43c3b98bf" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7fe3-8255-407646c34172" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_019e2791-2605-736b-b542-eeac32ae4a99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtConversionByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:to="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_019e2791-2605-736b-b542-eeac32ae4a99" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-736b-b542-eeac32ae4a99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtConversionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_019e2791-2605-736b-b542-eeac32ae4a99" xlink:to="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-736b-b542-eeac32ae4a99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtConversionNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_019e2791-2605-736b-b542-eeac32ae4a99" xlink:to="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtConversionScenarioOneMember_019e2791-2605-7e0f-b59f-56d511df4f1f" xlink:href="dbx-20260630.xsd#dbx_DebtConversionScenarioOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:to="loc_dbx_DebtConversionScenarioOneMember_019e2791-2605-7e0f-b59f-56d511df4f1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtConversionScenarioTwoMember_019e2791-2605-7710-b90f-578972e072f5" xlink:href="dbx-20260630.xsd#dbx_DebtConversionScenarioTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:to="loc_dbx_DebtConversionScenarioTwoMember_019e2791-2605-7710-b90f-578972e072f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtConversionScenarioThreeMember_019e2791-2605-7eb5-b93c-dd51b2f4bf40" xlink:href="dbx-20260630.xsd#dbx_DebtConversionScenarioThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:to="loc_dbx_DebtConversionScenarioThreeMember_019e2791-2605-7eb5-b93c-dd51b2f4bf40" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtConversionScenarioFourMember_019e2791-2605-7079-aadb-cf8733dbc7cd" xlink:href="dbx-20260630.xsd#dbx_DebtConversionScenarioFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_019e2791-2605-7cbf-96b8-44b39fb378ab" xlink:to="loc_dbx_DebtConversionScenarioFourMember_019e2791-2605-7079-aadb-cf8733dbc7cd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e2791-2605-76a6-894c-21d8f8d883fc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7c44-977e-eb701d4171bb" xlink:to="loc_srt_RangeAxis_019e2791-2605-76a6-894c-21d8f8d883fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2605-76a6-894c-21d8f8d883fc_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e2791-2605-76a6-894c-21d8f8d883fc" xlink:to="loc_srt_RangeMember_019e2791-2605-76a6-894c-21d8f8d883fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2605-71cd-907d-74daae11f877" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e2791-2605-76a6-894c-21d8f8d883fc" xlink:to="loc_srt_RangeMember_019e2791-2605-71cd-907d-74daae11f877" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e2791-2605-7b22-8828-cbb9e905685f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2605-71cd-907d-74daae11f877" xlink:to="loc_srt_MaximumMember_019e2791-2605-7b22-8828-cbb9e905685f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_019e2791-2605-7550-9fcd-8447be1c6e0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_019e2791-2605-7550-9fcd-8447be1c6e0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e2791-2605-7758-89ee-4893a6bd9d97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e2791-2605-7758-89ee-4893a6bd9d97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfConvertibleDebt_019e2791-2605-7258-9834-2933834c85b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_RepaymentsOfConvertibleDebt_019e2791-2605-7258-9834-2933834c85b8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_019e2791-2605-762c-8cdb-b45c69cf49f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_019e2791-2605-762c-8cdb-b45c69cf49f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_019e2791-2605-7880-a611-f692837674fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_019e2791-2605-7880-a611-f692837674fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_019e2791-2605-7283-943d-30beec6f92bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleThresholdTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdTradingDays_019e2791-2605-7283-943d-30beec6f92bb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_019e2791-2605-784a-8bba-d63cd85df9c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1_019e2791-2605-784a-8bba-d63cd85df9c2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_019e2791-2605-70c2-81cb-2b3aa352a33c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_019e2791-2605-70c2-81cb-2b3aa352a33c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_019e2791-2605-7b04-a410-477ae80d192a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_019e2791-2605-7b04-a410-477ae80d192a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_019e2791-2605-74a9-90e1-66a570535fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_019e2791-2605-74a9-90e1-66a570535fd0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019e2791-2605-7305-a451-c00bf14432e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentTerm_019e2791-2605-7305-a451-c00bf14432e8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019e2791-2605-708b-ba0c-d98db31a108b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_InterestExpenseDebt_019e2791-2605-708b-ba0c-d98db31a108b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e2791-2605-70c8-a20f-43c32db3039f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-7477-86dd-c8ea6358a380" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e2791-2605-70c8-a20f-43c32db3039f" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtScheduleofConvertibleNotesDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtScheduleofConvertibleNotesDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtScheduleofConvertibleNotesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e2791-2605-730f-930e-c0950563f9ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:to="loc_us-gaap_DebtInstrumentTable_019e2791-2605-730f-930e-c0950563f9ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-77c7-8ff3-1934a0625236" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-730f-930e-c0950563f9ed" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-77c7-8ff3-1934a0625236" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-77c7-8ff3-1934a0625236_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-77c7-8ff3-1934a0625236" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-77c7-8ff3-1934a0625236_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-71cc-8fc1-62661b8d615a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-77c7-8ff3-1934a0625236" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-71cc-8fc1-62661b8d615a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7a41-8e29-0314bbf55fa7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-71cc-8fc1-62661b8d615a" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7a41-8e29-0314bbf55fa7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019f7f35-ff52-79a7-9567-ff3be812a39a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-71cc-8fc1-62661b8d615a" xlink:to="loc_us-gaap_LineOfCreditMember_019f7f35-ff52-79a7-9567-ff3be812a39a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7644-aae1-a0c83ed6d60f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-730f-930e-c0950563f9ed" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7644-aae1-a0c83ed6d60f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7644-aae1-a0c83ed6d60f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7644-aae1-a0c83ed6d60f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7644-aae1-a0c83ed6d60f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bd6-83b7-a8b4ce721fc4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-7644-aae1-a0c83ed6d60f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bd6-83b7-a8b4ce721fc4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-7d31-95c6-6e365455e677" xlink:href="dbx-20260630.xsd#dbx_A2026ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bd6-83b7-a8b4ce721fc4" xlink:to="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-7d31-95c6-6e365455e677" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-701a-8b97-384bdab29e3c" xlink:href="dbx-20260630.xsd#dbx_A2028ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bd6-83b7-a8b4ce721fc4" xlink:to="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-701a-8b97-384bdab29e3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019f7f35-ff52-7be9-901a-8d565bd1319e" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-7bd6-83b7-a8b4ce721fc4" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019f7f35-ff52-7be9-901a-8d565bd1319e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019f7f35-ff52-7dd6-bfb1-39353d9bd09f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-730f-930e-c0950563f9ed" xlink:to="loc_us-gaap_CreditFacilityAxis_019f7f35-ff52-7dd6-bfb1-39353d9bd09f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019f7f35-ff52-7dd6-bfb1-39353d9bd09f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019f7f35-ff52-7dd6-bfb1-39353d9bd09f" xlink:to="loc_us-gaap_CreditFacilityDomain_019f7f35-ff52-7dd6-bfb1-39353d9bd09f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019f7f35-ff52-7475-af54-ab63c1d8ef83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019f7f35-ff52-7dd6-bfb1-39353d9bd09f" xlink:to="loc_us-gaap_CreditFacilityDomain_019f7f35-ff52-7475-af54-ab63c1d8ef83" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019f7f35-ff52-7ffc-a9cf-b1fc98716cdb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019f7f35-ff52-7475-af54-ab63c1d8ef83" xlink:to="loc_us-gaap_SecuredDebtMember_019f7f35-ff52-7ffc-a9cf-b1fc98716cdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7752-bdd8-1b5319eed714" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7752-bdd8-1b5319eed714" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_019e2791-2605-7444-9990-e6b7cb4b64cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnamortizedDebtIssuanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_019e2791-2605-7444-9990-e6b7cb4b64cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e2791-2605-75e6-85cc-bc7443819992" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:to="loc_us-gaap_LongTermDebt_019e2791-2605-75e6-85cc-bc7443819992" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_019f7f35-ff52-7898-88b3-066c01913178" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-741d-a7d6-f28f5afaa11e" xlink:to="loc_us-gaap_InterestExpenseDebt_019f7f35-ff52-7898-88b3-066c01913178" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtScheduleofMaturitiesofLongTermConvertibleDebtDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtScheduleofMaturitiesofLongTermConvertibleDebtDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtScheduleofMaturitiesofLongTermConvertibleDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7e61-ad8a-bf8e40a0b262" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7e61-ad8a-bf8e40a0b262" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7548-95f2-9b0bef7c1e1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7e61-ad8a-bf8e40a0b262" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7548-95f2-9b0bef7c1e1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7548-95f2-9b0bef7c1e1d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7548-95f2-9b0bef7c1e1d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7548-95f2-9b0bef7c1e1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c7c-be1a-46a176c7d1a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7548-95f2-9b0bef7c1e1d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c7c-be1a-46a176c7d1a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7e18-935a-bbb75ac76f28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c7c-be1a-46a176c7d1a5" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-7e18-935a-bbb75ac76f28" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019f9430-a4f1-7cc1-b850-d05c4750d09e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7c7c-be1a-46a176c7d1a5" xlink:to="loc_us-gaap_LineOfCreditMember_019f9430-a4f1-7cc1-b850-d05c4750d09e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019f9430-a4f1-7c9f-b803-ecc1a37e1f06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7e61-ad8a-bf8e40a0b262" xlink:to="loc_us-gaap_CreditFacilityAxis_019f9430-a4f1-7c9f-b803-ecc1a37e1f06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019f9430-a4f1-7c9f-b803-ecc1a37e1f06_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019f9430-a4f1-7c9f-b803-ecc1a37e1f06" xlink:to="loc_us-gaap_CreditFacilityDomain_019f9430-a4f1-7c9f-b803-ecc1a37e1f06_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019f9430-a4f1-72bd-8ba0-766a7f272d05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019f9430-a4f1-7c9f-b803-ecc1a37e1f06" xlink:to="loc_us-gaap_CreditFacilityDomain_019f9430-a4f1-72bd-8ba0-766a7f272d05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019f9430-a4f1-76a0-8ed2-4597d03e30be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019f9430-a4f1-72bd-8ba0-766a7f272d05" xlink:to="loc_us-gaap_SecuredDebtMember_019f9430-a4f1-76a0-8ed2-4597d03e30be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019f9430-a4f1-79ef-b409-986408120a20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e2791-2605-7e61-ad8a-bf8e40a0b262" xlink:to="loc_us-gaap_DebtInstrumentAxis_019f9430-a4f1-79ef-b409-986408120a20" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019f9430-a4f1-79ef-b409-986408120a20_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019f9430-a4f1-79ef-b409-986408120a20" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019f9430-a4f1-79ef-b409-986408120a20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019f9430-a4f1-757d-b5eb-905ffc72c443" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019f9430-a4f1-79ef-b409-986408120a20" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019f9430-a4f1-757d-b5eb-905ffc72c443" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_TermLoanCreditAgreementMember_019f9430-a4f1-7e96-bfa7-f4b9ebfbb17f" xlink:href="dbx-20260630.xsd#dbx_TermLoanCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019f9430-a4f1-757d-b5eb-905ffc72c443" xlink:to="loc_dbx_TermLoanCreditAgreementMember_019f9430-a4f1-7e96-bfa7-f4b9ebfbb17f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e2791-2605-7766-9f03-deaa04d46660" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e2791-2605-7766-9f03-deaa04d46660" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e2791-2605-7622-9969-5b5661d7aaf7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e2791-2605-7622-9969-5b5661d7aaf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e2791-2605-7952-8316-4aefc5a34ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e2791-2605-7952-8316-4aefc5a34ec4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e2791-2605-72dd-85b8-64fdab7c8528" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e2791-2605-72dd-85b8-64fdab7c8528" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019f9430-a4f1-704d-bf2b-efa647212b5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019f9430-a4f1-704d-bf2b-efa647212b5a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LongTermDebtMaturityYearFiveAndAfter_019f9430-a4f1-77dd-8ba9-c6d6ee5d2f65" xlink:href="dbx-20260630.xsd#dbx_LongTermDebtMaturityYearFiveAndAfter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_dbx_LongTermDebtMaturityYearFiveAndAfter_019f9430-a4f1-77dd-8ba9-c6d6ee5d2f65" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7bac-8d79-f124b3df66ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e2791-2605-78b7-acf4-a56726805f20" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e2791-2605-7bac-8d79-f124b3df66ee" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/DebtConvertibleNoteHedgesandWarrantsNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#DebtConvertibleNoteHedgesandWarrantsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/DebtConvertibleNoteHedgesandWarrantsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e2791-2605-743a-9568-6da719eb9761" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e2791-2605-743a-9568-6da719eb9761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-743a-9568-6da719eb9761_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e2791-2605-743a-9568-6da719eb9761" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-743a-9568-6da719eb9761_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-7b28-994c-ee7673224f10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e2791-2605-743a-9568-6da719eb9761" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-7b28-994c-ee7673224f10" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026NotesHedgeMember_019e2791-2605-7bde-894f-6821aa8eab41" xlink:href="dbx-20260630.xsd#dbx_A2026NotesHedgeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-7b28-994c-ee7673224f10" xlink:to="loc_dbx_A2026NotesHedgeMember_019e2791-2605-7bde-894f-6821aa8eab41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028NotesHedgeMember_019e2791-2605-7411-9117-1517994fd53c" xlink:href="dbx-20260630.xsd#dbx_A2028NotesHedgeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-7b28-994c-ee7673224f10" xlink:to="loc_dbx_A2028NotesHedgeMember_019e2791-2605-7411-9117-1517994fd53c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_ConvertibleNoteHedgeMember_019e2791-2605-788f-934b-19dfb30823ae" xlink:href="dbx-20260630.xsd#dbx_ConvertibleNoteHedgeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e2791-2605-7b28-994c-ee7673224f10" xlink:to="loc_dbx_ConvertibleNoteHedgeMember_019e2791-2605-788f-934b-19dfb30823ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-78a4-90fb-59482d0e32b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-78a4-90fb-59482d0e32b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-78a4-90fb-59482d0e32b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-78a4-90fb-59482d0e32b5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-78a4-90fb-59482d0e32b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-73d5-82da-84494417f099" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e2791-2605-78a4-90fb-59482d0e32b5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-73d5-82da-84494417f099" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-70d9-8f91-a0aa6de28e70" xlink:href="dbx-20260630.xsd#dbx_A2026ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-73d5-82da-84494417f099" xlink:to="loc_dbx_A2026ConvertibleNotesMember_019e2791-2605-70d9-8f91-a0aa6de28e70" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-7194-9b64-e7a3af5c263f" xlink:href="dbx-20260630.xsd#dbx_A2028ConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e2791-2605-73d5-82da-84494417f099" xlink:to="loc_dbx_A2028ConvertibleNotesMember_019e2791-2605-7194-9b64-e7a3af5c263f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7560-950f-77e876714ae5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7560-950f-77e876714ae5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7560-950f-77e876714ae5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7560-950f-77e876714ae5" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7560-950f-77e876714ae5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-70c0-bacd-75f399df179a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7560-950f-77e876714ae5" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-70c0-bacd-75f399df179a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-781d-a7b3-0137811cd107" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-70c0-bacd-75f399df179a" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e2791-2605-781d-a7b3-0137811cd107" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_019e2791-2605-7f2b-b975-cdad832793ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e2791-2605-7c3c-a0ec-1a07bc2a8889" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_019e2791-2605-7f2b-b975-cdad832793ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-7f2b-b975-cdad832793ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e2791-2605-7f2b-b975-cdad832793ab" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-7f2b-b975-cdad832793ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-769b-aff8-271fc3854597" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_019e2791-2605-7f2b-b975-cdad832793ab" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-769b-aff8-271fc3854597" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026WarrantsMember_019e2791-2605-7042-8a60-4380da9c81d0" xlink:href="dbx-20260630.xsd#dbx_A2026WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-769b-aff8-271fc3854597" xlink:to="loc_dbx_A2026WarrantsMember_019e2791-2605-7042-8a60-4380da9c81d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2028WarrantsMember_019e2791-2605-7a28-a8d1-866f0d692b21" xlink:href="dbx-20260630.xsd#dbx_A2028WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-769b-aff8-271fc3854597" xlink:to="loc_dbx_A2028WarrantsMember_019e2791-2605-7a28-a8d1-866f0d692b21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2026And2028WarrantsMember_019e2791-2605-703a-b4bb-981b03b4be46" xlink:href="dbx-20260630.xsd#dbx_A2026And2028WarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_019e2791-2605-769b-aff8-271fc3854597" xlink:to="loc_dbx_A2026And2028WarrantsMember_019e2791-2605-703a-b4bb-981b03b4be46" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_NumberOfSharesCoveredByHedge_019e2791-2605-7324-b7e9-a6a87cee214b" xlink:href="dbx-20260630.xsd#dbx_NumberOfSharesCoveredByHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_dbx_NumberOfSharesCoveredByHedge_019e2791-2605-7324-b7e9-a6a87cee214b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityStrikePrice1_019e2791-2605-7a97-a0f5-0ca4b41722d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OptionIndexedToIssuersEquityStrikePrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityStrikePrice1_019e2791-2605-7a97-a0f5-0ca4b41722d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeCostOfHedge_019e2791-2605-7a7c-923d-22fec15f52dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeCostOfHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_DerivativeCostOfHedge_019e2791-2605-7a7c-923d-22fec15f52dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfConvertibleDebt_019e2791-2605-76d6-9688-451728e55df1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_RepaymentsOfConvertibleDebt_019e2791-2605-76d6-9688-451728e55df1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e2791-2605-7b76-9439-2fe913aa8abe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019e2791-2605-7b76-9439-2fe913aa8abe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019e2791-2605-7988-a02f-bf4d2b39f744" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019e2791-2605-7988-a02f-bf4d2b39f744" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_019e2791-2605-7dec-b4de-42364deaa19b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_019e2791-2605-7dec-b4de-42364deaa19b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_019e2791-2605-77fa-9da9-8d28e90c2dee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_019e2791-2605-77fa-9da9-8d28e90c2dee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DebtInstrumentConvertibleEffectiveConversionPrice_019e2791-2605-745e-8acf-bf7343dc9e9b" xlink:href="dbx-20260630.xsd#dbx_DebtInstrumentConvertibleEffectiveConversionPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e2791-2605-7d2f-8b98-b6bf745effca" xlink:to="loc_dbx_DebtInstrumentConvertibleEffectiveConversionPrice_019e2791-2605-745e-8acf-bf7343dc9e9b" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#LeasesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e2791-2605-76af-9fd4-cb13da146a1a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:to="loc_srt_RangeAxis_019e2791-2605-76af-9fd4-cb13da146a1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2605-76af-9fd4-cb13da146a1a_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e2791-2605-76af-9fd4-cb13da146a1a" xlink:to="loc_srt_RangeMember_019e2791-2605-76af-9fd4-cb13da146a1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e2791-2605-7c84-a90f-54303e5b8618" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e2791-2605-76af-9fd4-cb13da146a1a" xlink:to="loc_srt_RangeMember_019e2791-2605-7c84-a90f-54303e5b8618" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e2791-2605-7eec-8c39-b1c364fedd12" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2605-7c84-a90f-54303e5b8618" xlink:to="loc_srt_MinimumMember_019e2791-2605-7eec-8c39-b1c364fedd12" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e2791-2605-7bb5-a758-370a90638389" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e2791-2605-7c84-a90f-54303e5b8618" xlink:to="loc_srt_MaximumMember_019e2791-2605-7bb5-a758-370a90638389" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermAxis_019e2791-2605-70d1-a5f0-d6ab09c090e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseContractualTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:to="loc_us-gaap_LeaseContractualTermAxis_019e2791-2605-70d1-a5f0-d6ab09c090e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_019e2791-2605-70d1-a5f0-d6ab09c090e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LeaseContractualTermAxis_019e2791-2605-70d1-a5f0-d6ab09c090e0" xlink:to="loc_us-gaap_LeaseContractualTermDomain_019e2791-2605-70d1-a5f0-d6ab09c090e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_019e2791-2605-7301-9cdd-cc2fa62421c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LeaseContractualTermAxis_019e2791-2605-70d1-a5f0-d6ab09c090e0" xlink:to="loc_us-gaap_LeaseContractualTermDomain_019e2791-2605-7301-9cdd-cc2fa62421c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CorporateHeadquartersLeaseMember_019e2791-2605-71dc-9180-f831a56303fe" xlink:href="dbx-20260630.xsd#dbx_CorporateHeadquartersLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseContractualTermDomain_019e2791-2605-7301-9cdd-cc2fa62421c4" xlink:to="loc_dbx_CorporateHeadquartersLeaseMember_019e2791-2605-71dc-9180-f831a56303fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7d3e-ae2c-59d216288d83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7d3e-ae2c-59d216288d83" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7d3e-ae2c-59d216288d83_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7d3e-ae2c-59d216288d83" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7d3e-ae2c-59d216288d83_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7e6c-932b-93db2db17cdc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e2791-2605-7d3e-ae2c-59d216288d83" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7e6c-932b-93db2db17cdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e2791-2605-795f-b471-40dc7aa8aadd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e2791-2605-7e6c-932b-93db2db17cdc" xlink:to="loc_us-gaap_LineOfCreditMember_019e2791-2605-795f-b471-40dc7aa8aadd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e2791-2605-7e03-b08d-216373977cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019e2791-2605-7f61-ab1e-9551dd08388d" xlink:to="loc_us-gaap_CreditFacilityAxis_019e2791-2605-7e03-b08d-216373977cb8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7e03-b08d-216373977cb8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-7e03-b08d-216373977cb8" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7e03-b08d-216373977cb8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7420-a18c-c8dad8ae811c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e2791-2605-7e03-b08d-216373977cb8" xlink:to="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7420-a18c-c8dad8ae811c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_019e2791-2605-79b3-a9f3-9228bea5aa3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e2791-2605-7420-a18c-c8dad8ae811c" xlink:to="loc_us-gaap_LetterOfCreditMember_019e2791-2605-79b3-a9f3-9228bea5aa3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_019e2791-2605-7f3c-b272-96c11f437af5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_019e2791-2605-7f3c-b272-96c11f437af5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_019e2791-2605-7a7f-96d4-61e754c8d952" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_019e2791-2605-7a7f-96d4-61e754c8d952" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LesseeOperatingSubleaseRemainingLeaseTerm_019e2791-2605-719e-a4c7-128170120e47" xlink:href="dbx-20260630.xsd#dbx_LesseeOperatingSubleaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_dbx_LesseeOperatingSubleaseRemainingLeaseTerm_019e2791-2605-719e-a4c7-128170120e47" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LesseeOperatingSubleaseExtensionTerm_019e2791-2605-70ea-ac38-f518dad7f32d" xlink:href="dbx-20260630.xsd#dbx_LesseeOperatingSubleaseExtensionTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_dbx_LesseeOperatingSubleaseExtensionTerm_019e2791-2605-70ea-ac38-f518dad7f32d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome_019e2791-2605-70ec-aa16-41a3b5fc1b34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubleaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_SubleaseIncome_019e2791-2605-70ec-aa16-41a3b5fc1b34" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e2791-2605-793a-aeb5-89569d561ab0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_019e2791-2605-793a-aeb5-89569d561ab0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2605-72cb-8d4e-0289da607e11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e2791-2605-72cb-8d4e-0289da607e11" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_OperatingLeaseMinimumObligations_019e2791-2605-72f9-b67e-da337e40e262" xlink:href="dbx-20260630.xsd#dbx_OperatingLeaseMinimumObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_dbx_OperatingLeaseMinimumObligations_019e2791-2605-72f9-b67e-da337e40e262" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_019e2791-2605-78f9-9b70-fd2095376047" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019e2791-2605-73bc-8fd2-530b0e66fe04" xlink:to="loc_us-gaap_AssetImpairmentCharges_019e2791-2605-78f9-9b70-fd2095376047" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/StockholdersDeficitCommonstockandpreferredstockNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#StockholdersDeficitCommonstockandpreferredstockNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/StockholdersDeficitCommonstockandpreferredstockNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e2791-2605-7986-9446-0604d2cf7989" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e2791-2605-7986-9446-0604d2cf7989" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2605-7986-9446-0604d2cf7989_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2605-7986-9446-0604d2cf7989" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2605-7986-9446-0604d2cf7989_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2605-78ca-975e-f3d9c76af477" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2605-7986-9446-0604d2cf7989" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2605-78ca-975e-f3d9c76af477" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019e2791-2605-7a9e-a72c-890380e9e7c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2605-78ca-975e-f3d9c76af477" xlink:to="loc_us-gaap_CommonClassAMember_019e2791-2605-7a9e-a72c-890380e9e7c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019e2791-2605-7dc6-b8c8-3ba11679b14f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2605-78ca-975e-f3d9c76af477" xlink:to="loc_us-gaap_CommonClassBMember_019e2791-2605-7dc6-b8c8-3ba11679b14f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassCMember_019e2791-2605-7db2-8c31-5c1d04fa9c34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2605-78ca-975e-f3d9c76af477" xlink:to="loc_us-gaap_CommonClassCMember_019e2791-2605-7db2-8c31-5c1d04fa9c34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019e2791-2605-77f6-9e98-f3a1d154776f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:to="loc_us-gaap_PlanNameAxis_019e2791-2605-77f6-9e98-f3a1d154776f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2605-77f6-9e98-f3a1d154776f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2605-77f6-9e98-f3a1d154776f" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2605-77f6-9e98-f3a1d154776f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2605-7acc-844e-ae47deaf5737" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2605-77f6-9e98-f3a1d154776f" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2605-7acc-844e-ae47deaf5737" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CoFounderGrantsMember_019e2791-2605-746b-8c59-bdb0ae47f39d" xlink:href="dbx-20260630.xsd#dbx_CoFounderGrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019e2791-2605-7acc-844e-ae47deaf5737" xlink:to="loc_dbx_CoFounderGrantsMember_019e2791-2605-746b-8c59-bdb0ae47f39d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e2791-2605-7a14-8c20-88c42b061d29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:to="loc_us-gaap_AwardTypeAxis_019e2791-2605-7a14-8c20-88c42b061d29" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2605-7a14-8c20-88c42b061d29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2605-7a14-8c20-88c42b061d29" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2605-7a14-8c20-88c42b061d29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2605-7d21-82a3-352bf7c7875d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2605-7a14-8c20-88c42b061d29" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2605-7d21-82a3-352bf7c7875d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_019e2791-2605-7fd4-868b-2aad924a79d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2605-7d21-82a3-352bf7c7875d" xlink:to="loc_us-gaap_RestrictedStockMember_019e2791-2605-7fd4-868b-2aad924a79d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_019e2791-2605-7a80-a782-27761c34e501" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2605-77e1-8fbb-342440037519" xlink:to="loc_srt_TitleOfIndividualAxis_019e2791-2605-7a80-a782-27761c34e501" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2605-7a80-a782-27761c34e501_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2605-7a80-a782-27761c34e501" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2605-7a80-a782-27761c34e501_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2605-754a-8edd-968fdeaef8a1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2605-7a80-a782-27761c34e501" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2605-754a-8edd-968fdeaef8a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ChiefExecutiveOfficerMember_019e2791-2606-7d54-bba6-58e117d35b15" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ChiefExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2605-754a-8edd-968fdeaef8a1" xlink:to="loc_srt_ChiefExecutiveOfficerMember_019e2791-2606-7d54-bba6-58e117d35b15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CommonStockVoteEquivalent_019e2791-2606-72a4-9fa0-4f8ae7c4487c" xlink:href="dbx-20260630.xsd#dbx_CommonStockVoteEquivalent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_dbx_CommonStockVoteEquivalent_019e2791-2606-72a4-9fa0-4f8ae7c4487c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019e2791-2606-71b7-860a-c9fc9d6b52f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019e2791-2606-71b7-860a-c9fc9d6b52f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e2791-2606-732e-a433-2d6139405a44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e2791-2606-732e-a433-2d6139405a44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockSharesConverted1_019e2791-2606-71df-999b-3d367a0b347e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockSharesConverted1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_ConversionOfStockSharesConverted1_019e2791-2606-71df-999b-3d367a0b347e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e2791-2606-7c36-8c84-b3c75c1cc2d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e2791-2606-7c36-8c84-b3c75c1cc2d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e2791-2606-7a71-a220-33125f8c23d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e2791-2606-7a71-a220-33125f8c23d4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7562-9be5-fcc790d8abaf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7562-9be5-fcc790d8abaf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019e2791-2606-73cb-bc0b-db84a1cc0925" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-790c-99ea-8b68c20408d6" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019e2791-2606-73cb-bc0b-db84a1cc0925" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/StockholdersDeficitStockrepurchaseprogramNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#StockholdersDeficitStockrepurchaseprogramNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/StockholdersDeficitStockrepurchaseprogramNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-7be1-ae2d-47acb480f43b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-7be1-ae2d-47acb480f43b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-7829-bb42-2049f14012cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-7be1-ae2d-47acb480f43b" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-7829-bb42-2049f14012cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7829-bb42-2049f14012cd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-7829-bb42-2049f14012cd" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7829-bb42-2049f14012cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7b0d-b784-9122603cffac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-7829-bb42-2049f14012cd" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7b0d-b784-9122603cffac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019e2791-2606-7879-af93-d21e596e541c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7b0d-b784-9122603cffac" xlink:to="loc_us-gaap_CommonClassAMember_019e2791-2606-7879-af93-d21e596e541c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019fa8df-0e40-74f1-891c-138e12bd9a02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_019fa8df-0e40-74f1-891c-138e12bd9a02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_ShareRepurchaseProgramAuthorizedAdditionalAmount_019e2791-2606-7e05-8f8e-15279deca45d" xlink:href="dbx-20260630.xsd#dbx_ShareRepurchaseProgramAuthorizedAdditionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:to="loc_dbx_ShareRepurchaseProgramAuthorizedAdditionalAmount_019e2791-2606-7e05-8f8e-15279deca45d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e2791-2606-7daa-b2f7-7a5a804ac169" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e2791-2606-7daa-b2f7-7a5a804ac169" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e2791-2606-7a65-8ca0-5436ea31a4b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7e16-92b1-f4f199b16da3" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e2791-2606-7a65-8ca0-5436ea31a4b8" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/StockholdersDeficitEquityincentiveplansNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#StockholdersDeficitEquityincentiveplansNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/StockholdersDeficitEquityincentiveplansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7da5-a1b5-c4c816849eae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7da5-a1b5-c4c816849eae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019e2791-2606-7166-a739-e8901b5cf332" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7da5-a1b5-c4c816849eae" xlink:to="loc_us-gaap_PlanNameAxis_019e2791-2606-7166-a739-e8901b5cf332" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2606-7166-a739-e8901b5cf332_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2606-7166-a739-e8901b5cf332" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2606-7166-a739-e8901b5cf332_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2606-78ff-b8ce-2f97287bcffb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2606-7166-a739-e8901b5cf332" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2606-78ff-b8ce-2f97287bcffb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_A2018PlanMember_019e2791-2606-7fc8-8342-3eaa89fe915c" xlink:href="dbx-20260630.xsd#dbx_A2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019e2791-2606-78ff-b8ce-2f97287bcffb" xlink:to="loc_dbx_A2018PlanMember_019e2791-2606-7fc8-8342-3eaa89fe915c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DropboxHelloSignAndDocSendEquityIncentivePlansMember_019e2791-2606-75f4-b635-07958b64a682" xlink:href="dbx-20260630.xsd#dbx_DropboxHelloSignAndDocSendEquityIncentivePlansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019e2791-2606-78ff-b8ce-2f97287bcffb" xlink:to="loc_dbx_DropboxHelloSignAndDocSendEquityIncentivePlansMember_019e2791-2606-75f4-b635-07958b64a682" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e2791-2606-7501-9af0-6066e3e0315b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e2791-2606-7501-9af0-6066e3e0315b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e2791-2606-7835-b070-d914b0a6c81b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e2791-2606-7835-b070-d914b0a6c81b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019e2791-2606-73df-9fd5-a665dfa69757" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019e2791-2606-73df-9fd5-a665dfa69757" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_019e2791-2606-7771-b4c3-d6ca61c0adb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_019e2791-2606-7771-b4c3-d6ca61c0adb7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019e2791-2606-7eae-934c-d34b6d36f50a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7bb2-aace-48384ab2493f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019e2791-2606-7eae-934c-d34b6d36f50a" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/StockholdersDeficitScheduleofStockOptionandRestrictedStockActivityDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#StockholdersDeficitScheduleofStockOptionandRestrictedStockActivityDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/StockholdersDeficitScheduleofStockOptionandRestrictedStockActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7c9d-9880-08556724525e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7c9d-9880-08556724525e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e2791-2606-7ac7-b0f9-377080eed9e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7c9d-9880-08556724525e" xlink:to="loc_us-gaap_AwardTypeAxis_019e2791-2606-7ac7-b0f9-377080eed9e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7ac7-b0f9-377080eed9e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2606-7ac7-b0f9-377080eed9e9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7ac7-b0f9-377080eed9e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7c18-ac58-2e5e375a6473" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2606-7ac7-b0f9-377080eed9e9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7c18-ac58-2e5e375a6473" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_019e2791-2606-7be0-81b8-385a2b897b5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7c18-ac58-2e5e375a6473" xlink:to="loc_us-gaap_RestrictedStockMember_019e2791-2606-7be0-81b8-385a2b897b5b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:href="dbx-20260630.xsd#dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019e2791-2606-7f5d-9b37-9ce3436bcde0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019e2791-2606-7f5d-9b37-9ce3436bcde0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_019e2791-2606-736e-9f96-1718cd66def4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_019e2791-2606-736e-9f96-1718cd66def4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesCanceled_019e2791-2606-7949-85dc-85ce2e699aa1" xlink:href="dbx-20260630.xsd#dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesCanceled"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:to="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesCanceled_019e2791-2606-7949-85dc-85ce2e699aa1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e2791-2606-76dd-a01d-01975664d01e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e2791-2606-76dd-a01d-01975664d01e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_ShareBasedCompensationArrangementBySharebasedPaymentAwardDecreaseInNumberofSharesAuthorizedFromStockGranted_019e2791-2606-7562-8919-ecb1ed0de03c" xlink:href="dbx-20260630.xsd#dbx_ShareBasedCompensationArrangementBySharebasedPaymentAwardDecreaseInNumberofSharesAuthorizedFromStockGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dbx_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceRollForward_019e2791-2606-716a-a4cc-2ad09a3bb61a" xlink:to="loc_dbx_ShareBasedCompensationArrangementBySharebasedPaymentAwardDecreaseInNumberofSharesAuthorizedFromStockGranted_019e2791-2606-7562-8919-ecb1ed0de03c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019e2791-2606-7b49-b255-146b8c86d928" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_019e2791-2606-7eed-8eff-d868de3ed78a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_019e2791-2606-7eed-8eff-d868de3ed78a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e2791-2606-7312-8fea-0f502ac1f98c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_019e2791-2606-7eed-8eff-d868de3ed78a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e2791-2606-7312-8fea-0f502ac1f98c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e2791-2606-73d4-bbea-fb7112312823" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e2791-2606-77df-bb13-3f4be2575dea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e2791-2606-77df-bb13-3f4be2575dea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriod_019e2791-2606-7391-8c46-9eb58927ea83" xlink:href="dbx-20260630.xsd#dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:to="loc_dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriod_019e2791-2606-7391-8c46-9eb58927ea83" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e2791-2606-7a1d-840d-adae25dcf649" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e2791-2606-7a1d-840d-adae25dcf649" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7f31-bb54-252292f399ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e2791-2606-78da-b629-734b3792f572" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7f31-bb54-252292f399ac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e2791-2606-7aff-9c82-74d7296493b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e2791-2606-77e3-86b0-e1884e49cb0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e2791-2606-77e3-86b0-e1884e49cb0e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e2791-2606-74c0-a3e1-3aedc3add2dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e2791-2606-74c0-a3e1-3aedc3add2dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriodWeightedAverageGrantDateFairValue_019e2791-2606-7c3a-a9e0-8e906bc64580" xlink:href="dbx-20260630.xsd#dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:to="loc_dbx_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsReleasedinPeriodWeightedAverageGrantDateFairValue_019e2791-2606-7c3a-a9e0-8e906bc64580" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019e2791-2606-71b3-996a-5730d282167d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019e2791-2606-71b3-996a-5730d282167d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019e2791-2606-765b-bfb5-6adf660d7fa4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e2791-2606-7131-8e43-bab1c7b83d31" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019e2791-2606-765b-bfb5-6adf660d7fa4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e2791-2606-75cf-aa1d-586c5f048727" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019e2791-2606-76dc-bf8b-0d46460e6f50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7277-8720-46b97904af0d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019e2791-2606-76dc-bf8b-0d46460e6f50" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/StockholdersDeficitCoFounderGrantNarrativeDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#StockholdersDeficitCoFounderGrantNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/StockholdersDeficitCoFounderGrantNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7786-a20b-f2591d3fe2d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7786-a20b-f2591d3fe2d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019e2791-2606-7553-9ab0-2a27c8bb6540" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7786-a20b-f2591d3fe2d6" xlink:to="loc_us-gaap_PlanNameAxis_019e2791-2606-7553-9ab0-2a27c8bb6540" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2606-7553-9ab0-2a27c8bb6540_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2606-7553-9ab0-2a27c8bb6540" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2606-7553-9ab0-2a27c8bb6540_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019e2791-2606-777e-ae63-ebb8946812c8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019e2791-2606-7553-9ab0-2a27c8bb6540" xlink:to="loc_us-gaap_PlanNameDomain_019e2791-2606-777e-ae63-ebb8946812c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CoFounderGrantsMember_019e2791-2606-77d2-9af0-1d9a0d93bfc9" xlink:href="dbx-20260630.xsd#dbx_CoFounderGrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019e2791-2606-777e-ae63-ebb8946812c8" xlink:to="loc_dbx_CoFounderGrantsMember_019e2791-2606-77d2-9af0-1d9a0d93bfc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_019e2791-2606-7972-8a57-3c3504294ae0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7786-a20b-f2591d3fe2d6" xlink:to="loc_srt_TitleOfIndividualAxis_019e2791-2606-7972-8a57-3c3504294ae0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2606-7972-8a57-3c3504294ae0_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2606-7972-8a57-3c3504294ae0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2606-7972-8a57-3c3504294ae0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2606-7c6b-886d-853c7bf86777" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_019e2791-2606-7972-8a57-3c3504294ae0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2606-7c6b-886d-853c7bf86777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ChiefExecutiveOfficerMember_019e2791-2606-755c-aa74-482a7d212499" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ChiefExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e2791-2606-7c6b-886d-853c7bf86777" xlink:to="loc_srt_ChiefExecutiveOfficerMember_019e2791-2606-755c-aa74-482a7d212499" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e2791-2606-794b-842a-1ad147612e10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e2791-2606-7786-a20b-f2591d3fe2d6" xlink:to="loc_us-gaap_AwardTypeAxis_019e2791-2606-794b-842a-1ad147612e10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-794b-842a-1ad147612e10_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2606-794b-842a-1ad147612e10" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-794b-842a-1ad147612e10_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7bfe-a732-f494871e9caa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e2791-2606-794b-842a-1ad147612e10" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7bfe-a732-f494871e9caa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_019e2791-2606-772d-a864-feb624f8d102" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e2791-2606-7bfe-a732-f494871e9caa" xlink:to="loc_us-gaap_RestrictedStockMember_019e2791-2606-772d-a864-feb624f8d102" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7557-ab04-6f0466d568a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e2791-2606-7557-ab04-6f0466d568a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e2791-2606-7b35-af92-1426442e2c67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e2791-2606-7b35-af92-1426442e2c67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockPriceTargetMeasurementPeriodTradingPeriod_019e2791-2606-7a78-81ef-44c99443d99e" xlink:href="dbx-20260630.xsd#dbx_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockPriceTargetMeasurementPeriodTradingPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:to="loc_dbx_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockPriceTargetMeasurementPeriodTradingPeriod_019e2791-2606-7a78-81ef-44c99443d99e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e2791-2606-7c2a-930c-eb5cc7cea798" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e2791-2606-7ed3-84a8-58cce4493063" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e2791-2606-7c2a-930c-eb5cc7cea798" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/NetIncomePerShareScheduleofNumeratorsandDenominatorsofBasicandDilutedEPSComputationsDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#NetIncomePerShareScheduleofNumeratorsandDenominatorsofBasicandDilutedEPSComputationsDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/NetIncomePerShareScheduleofNumeratorsandDenominatorsofBasicandDilutedEPSComputationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7c85-9dd9-e6eb7e7b314b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-703a-805c-22839fbecd12" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7c85-9dd9-e6eb7e7b314b" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-703a-805c-22839fbecd12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-79bd-aafa-c690d2c1c467" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019e2791-2606-703a-805c-22839fbecd12" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-79bd-aafa-c690d2c1c467" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2606-79bd-aafa-c690d2c1c467_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-79bd-aafa-c690d2c1c467" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2606-79bd-aafa-c690d2c1c467_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7ce3-9b3b-ac07e54732c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e2791-2606-79bd-aafa-c690d2c1c467" xlink:to="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7ce3-9b3b-ac07e54732c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019e2791-2606-795c-989c-bb43238f1d21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7ce3-9b3b-ac07e54732c4" xlink:to="loc_us-gaap_CommonClassAMember_019e2791-2606-795c-989c-bb43238f1d21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019e2791-2606-73c0-8797-ff066f51c931" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e2791-2606-7ce3-9b3b-ac07e54732c4" xlink:to="loc_us-gaap_CommonClassBMember_019e2791-2606-73c0-8797-ff066f51c931" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7c85-9dd9-e6eb7e7b314b" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e2791-2606-74e9-aeb4-c89f0adbd45e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_us-gaap_NetIncomeLoss_019e2791-2606-74e9-aeb4-c89f0adbd45e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e2791-2606-78e9-ace0-254e97eeae91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e2791-2606-78e9-ace0-254e97eeae91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e2791-2606-7959-9dc9-c7fe80ec347c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_us-gaap_EarningsPerShareBasic_019e2791-2606-7959-9dc9-c7fe80ec347c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther_019e2791-2606-7bc9-b87f-d405bd8de70e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther_019e2791-2606-7bc9-b87f-d405bd8de70e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DilutiveSecuritiesEffectOnBasicEPSDilutiveEffectOfReallocation_019e2791-2606-7661-9167-cd600825c266" xlink:href="dbx-20260630.xsd#dbx_DilutiveSecuritiesEffectOnBasicEPSDilutiveEffectOfReallocation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_dbx_DilutiveSecuritiesEffectOnBasicEPSDilutiveEffectOfReallocation_019e2791-2606-7661-9167-cd600825c266" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019e2791-2606-7f06-a0bf-8816c3890a1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019e2791-2606-7d8d-b187-62aeb4660555" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019e2791-2606-7f06-a0bf-8816c3890a1c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019e2791-2606-7c85-9dd9-e6eb7e7b314b" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e2791-2606-7b66-9d31-f7ae763bee5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e2791-2606-7e33-b9c1-cac1e23ff40e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e2791-2606-7e33-b9c1-cac1e23ff40e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_IncrementalCommonSharesAttributabletoDilutiveEffectofConversionofCommonStock_019e2791-2606-7b13-b8c6-70afa7c67838" xlink:href="dbx-20260630.xsd#dbx_IncrementalCommonSharesAttributabletoDilutiveEffectofConversionofCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:to="loc_dbx_IncrementalCommonSharesAttributabletoDilutiveEffectofConversionofCommonStock_019e2791-2606-7b13-b8c6-70afa7c67838" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e2791-2606-7297-8089-be988593060c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e2791-2606-7297-8089-be988593060c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e2791-2606-7c49-ae65-07c8e898a618" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_019e2791-2606-7fee-ae07-7dd4e475ae52" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019e2791-2606-7c49-ae65-07c8e898a618" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/NetIncomePerShareScheduleofWeightedAverageImpactofPotentiallyDilutiveSecuritiesDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#NetIncomePerShareScheduleofWeightedAverageImpactofPotentiallyDilutiveSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/NetIncomePerShareScheduleofWeightedAverageImpactofPotentiallyDilutiveSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e2791-2606-7776-b850-9070e57d2e67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e2791-2606-7718-a5ff-38d4e4110689" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e2791-2606-7776-b850-9070e57d2e67" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e2791-2606-7718-a5ff-38d4e4110689" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e2791-2606-777e-bbbe-827cfed49fce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e2791-2606-7718-a5ff-38d4e4110689" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e2791-2606-777e-bbbe-827cfed49fce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-777e-bbbe-827cfed49fce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e2791-2606-777e-bbbe-827cfed49fce" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-777e-bbbe-827cfed49fce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e2791-2606-777e-bbbe-827cfed49fce" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019e2791-2606-7e18-89c8-361daaa32dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019e2791-2606-7e18-89c8-361daaa32dd4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_CoFounderGrantsMember_019e2791-2606-728b-b4db-1650fea39682" xlink:href="dbx-20260630.xsd#dbx_CoFounderGrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:to="loc_dbx_CoFounderGrantsMember_019e2791-2606-728b-b4db-1650fea39682" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_019e2791-2606-7d33-a68c-11700243a3d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_019e2791-2606-7d33-a68c-11700243a3d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_019e2791-2606-7ea3-9069-f7c53be55860" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019e2791-2606-7bc3-8833-dde4539f0f3c" xlink:to="loc_us-gaap_WarrantMember_019e2791-2606-7ea3-9069-f7c53be55860" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e2791-2606-7049-b983-0e3399f361bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e2791-2606-7776-b850-9070e57d2e67" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e2791-2606-7049-b983-0e3399f361bc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.dropbox.com/role/SegmentInformationandGeographicAreasDetails" xlink:type="simple" xlink:href="dbx-20260630.xsd#SegmentInformationandGeographicAreasDetails"/>
  <link:definitionLink xlink:role="http://www.dropbox.com/role/SegmentInformationandGeographicAreasDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e2791-2606-7e2c-943b-fb8439f58a6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e2791-2606-7e2c-943b-fb8439f58a6c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019e2791-2606-75d8-a094-99936a3026da" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e2791-2606-7e2c-943b-fb8439f58a6c" xlink:to="loc_srt_StatementGeographicalAxis_019e2791-2606-75d8-a094-99936a3026da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e2791-2606-75d8-a094-99936a3026da_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019e2791-2606-75d8-a094-99936a3026da" xlink:to="loc_srt_SegmentGeographicalDomain_019e2791-2606-75d8-a094-99936a3026da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e2791-2606-775e-b8ba-88a5eb3707c0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019e2791-2606-75d8-a094-99936a3026da" xlink:to="loc_srt_SegmentGeographicalDomain_019e2791-2606-775e-b8ba-88a5eb3707c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019e2791-2606-7442-90f9-11d9b38003b1" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e2791-2606-775e-b8ba-88a5eb3707c0" xlink:to="loc_country_US_019e2791-2606-7442-90f9-11d9b38003b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_019e2791-2606-758f-a2f5-b570d58252cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e2791-2606-775e-b8ba-88a5eb3707c0" xlink:to="loc_us-gaap_NonUsMember_019e2791-2606-758f-a2f5-b570d58252cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_019e2791-2606-754c-adea-aa2bee7ad23f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:to="loc_us-gaap_NumberOfOperatingSegments_019e2791-2606-754c-adea-aa2bee7ad23f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019e2791-2606-791e-9852-2a1b99290446" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:to="loc_us-gaap_NumberOfReportableSegments_019e2791-2606-791e-9852-2a1b99290446" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e2791-2606-77c9-a99d-521ece0df45b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e2791-2606-77c9-a99d-521ece0df45b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e2791-2606-702d-897a-1551cf0a87f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e2791-2606-7123-bb41-b4f663cfeecc" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e2791-2606-702d-897a-1551cf0a87f6" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_AliDasdanMember_019fa8e4-4733-7c12-a5a3-d9257bcb479f" xlink:href="dbx-20260630.xsd#dbx_AliDasdanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_AliDasdanMember_019fa8e4-4733-7c12-a5a3-d9257bcb479f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_SarahSchubachMember_019fa8e5-a63d-7675-a3ee-f5e8351878ef" xlink:href="dbx-20260630.xsd#dbx_SarahSchubachMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_SarahSchubachMember_019fa8e5-a63d-7675-a3ee-f5e8351878ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_LisaCampbellMember_019e2791-237a-7416-be6c-8969f4266ea5" xlink:href="dbx-20260630.xsd#dbx_LisaCampbellMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_LisaCampbellMember_019e2791-237a-7416-be6c-8969f4266ea5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_WillYoonMember_019fa8f0-82b5-796e-ba06-ab304bd881a7" xlink:href="dbx-20260630.xsd#dbx_WillYoonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_WillYoonMember_019fa8f0-82b5-796e-ba06-ab304bd881a7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_RossTennenbaumMember_019fa8f1-66be-7f2e-a446-60bedf5de619" xlink:href="dbx-20260630.xsd#dbx_RossTennenbaumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_RossTennenbaumMember_019fa8f1-66be-7f2e-a446-60bedf5de619" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DrewHoustonMember_019fa8f5-15f1-78b3-86b0-14d6d17ea913" xlink:href="dbx-20260630.xsd#dbx_DrewHoustonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_DrewHoustonMember_019fa8f5-15f1-78b3-86b0-14d6d17ea913" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_AshrafAlkarmiMember_019fa8f6-537d-7055-97a0-cd5223ab17ce" xlink:href="dbx-20260630.xsd#dbx_AshrafAlkarmiMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_dbx_AshrafAlkarmiMember_019fa8f6-537d-7055-97a0-cd5223ab17ce" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#TradingArrangmentsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllTradingArrangementsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllTradingArrangementsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DrewHoustonClassACommonStockMember_019fa8f7-67da-7d60-bac1-1d556701865f" xlink:href="dbx-20260630.xsd#dbx_DrewHoustonClassACommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_dbx_DrewHoustonClassACommonStockMember_019fa8f7-67da-7d60-bac1-1d556701865f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dbx_DrewHoustonClassBCommonStockMember_019fa8f7-b6db-7fcc-bd33-a1d24f649b3d" xlink:href="dbx-20260630.xsd#dbx_DrewHoustonClassBCommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_dbx_DrewHoustonClassBCommonStockMember_019fa8f7-b6db-7fcc-bd33-a1d24f649b3d" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
