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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2011-06-08</periodOfReport>

    <dateOfOriginalSubmission>2011-06-10</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001497770</issuerCik>
        <issuerName>Walker &amp; Dunlop, Inc.</issuerName>
        <issuerTradingSymbol>WD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001503843</rptOwnerCik>
            <rptOwnerName>Taylor Edmund Frederick</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>96 CLIFFIELD ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BEDFORD</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10506</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000824468</rptOwnerCik>
            <rptOwnerName>CREDIT SUISSE AG/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SEE FOOTNOTE (1) IN EXHIBIT 99.1</rptOwnerStreet1>
            <rptOwnerStreet2>11 MADISON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10010</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>2011-06-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2302</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4302</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5289937</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of restricted common stock granted by the Issuer pursuant to the terms of its 2010 Equity Incentive Plan to Edmund F. Taylor for serving as a director of the Issuer.  Mr. Taylor is a managing director of Credit Suisse Securities (USA) LLC, and pursuant to an arrangement, any director compensation received by him while so employed is paid over to or held for the benefit of Credit Suisse Securities (USA) LLC, or an affiliate thereof.  Upon vesting, the shares are to be transferred to Credit Suisse Securities (USA) LLC, or an affiliate thereof, for no additional consideration.</footnote>
        <footnote id="F2">Shares vest on June 8, 2012.</footnote>
        <footnote id="F3">See note (1) on Exhibit 99.1.</footnote>
        <footnote id="F4">See note (2) on Exhibit 99.1.</footnote>
        <footnote id="F5">See note (3) on Exhibit 99.1.</footnote>
    </footnotes>

    <remarks>Exhibit 99.1 and Joint Filing Information incorporated herein by reference.  This amendment restates the original Form 4 and is made principally to add an additional reporting person and to indicate that Mr. Taylor directly holds shares for the benefit of such additional reporting person.</remarks>

    <ownerSignature>
        <signatureName>/s/ Edmund F. Taylor</signatureName>
        <signatureDate>2012-02-21</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Louise Guarneri, Managing Director on behalf of Credit Suisse AG</signatureName>
        <signatureDate>2012-02-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
