<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-10-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001390844</issuerCik>
        <issuerName>WABCO Holdings Inc.</issuerName>
        <issuerTradingSymbol>WBC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001193795</rptOwnerCik>
            <rptOwnerName>STEBBINS DONALD J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WABCO HOLDINGS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE CENTENNIAL AVENUE</rptOwnerStreet2>
            <rptOwnerCity>PISCATAWAY</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08855</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-10-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25.685</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>58.40</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9679.237</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Deferred Compensation Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3780</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Deferred Stock Units</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5469.329</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents meeting fee paid to non-management directors, receipt of which Director elected to defer pursuant to the WABCO Holdings Inc. Deferred Compensation Plan and which shares are allocated to Director's Stock Account under the Plan.</footnote>
        <footnote id="F2">The deferred stock units were granted as part of the reporting person's annual retainer. The deferred stock units equal the reporting person's portion of his retainer fee divided by the closing price of WABCO's common stock on the day preceding the grant date. Each whole deferred stock unit represents a contingent right to receive one share of WABCO common stock. The deferred stock units are 100% vested upon grant and shall be distributed in shares of common stock as soon as practicable following the earliest to occur of: (i) reporting person's death or Disability as defined in the Award Agreement; (ii) a &quot;Change in Control&quot; as defined in the Omnibus Incentive Plan; (iii) the reporting person's &quot;separation from service&quot; (as defined under applicable tax rules) from WABCO Holding Inc.; (iv) 13 months after the grant date; or (v) if elected by the reporting person, an &quot;optional payment date&quot; which may not be earlier than 5 years and one month after the grant date.</footnote>
        <footnote id="F3">Shares are held in a Rabbi trust for non-management directors. Director exercises voting rights but no rights to dispose until directorship terminates.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Thomas P. Conaghan, Attorney-in-Fact</signatureName>
        <signatureDate>2012-10-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
