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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-11-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001490281</issuerCik>
        <issuerName>Groupon, Inc.</issuerName>
        <issuerTradingSymbol>GRPN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001114238</rptOwnerCik>
            <rptOwnerName>KEYWELL BRADLEY A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GROUPON, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>600 WEST CHICAGO AVENUE, SUITE 620</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60654</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40825030</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Deferred Stock Unit (Right to Receive)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2012-11-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5781.938</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5781.938</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15420.071</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-11-03</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-10-31</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>400008</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>400008</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9149</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9149</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares of Class A Common Stock reported on this line are held by Rugger Ventures LLC, an entity owned by Kimberly Keywell (80%), the wife of Bradley A. Keywell, and Mr. Keywell's children (20%).</footnote>
        <footnote id="F2">Mr. Keywell has received an exempt award of Deferred Stock Units (&quot;DSUs&quot;) under the Groupon, Inc. Non-Employee Director Compensation Plan. DSUs represent a right to receive shares of Class A common stock (or, in the sole discretion of Groupon's Board of Directors following a change in control, cash, securities or a combination of cash and securities equal to the fair market value thereof) upon termination of service as a Director of Groupon. The Mr. Keywell has elected to receive DSUs in lieu of the annual retainer fees payable for services on Groupon's Board of Directors and any committees thereof. The DSUs are awarded on the date such fees would otherwise be payable (i.e., quarterly in arrears). The DSUs are immediately vested.</footnote>
        <footnote id="F3">Each share of Class B Common Stock is convertible at any time at the option of the holder into one share of Class A Common Stock. The Class A Common Stock and Class B Common Stock will each convert automatically into a single class of Common Stock on October 31, 2016.</footnote>
        <footnote id="F4">In addition to the disclosure in footnote (3) each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon (i) the date specified by the affirmative vote or written consent of the holders of at least 66 2/3% of the outstanding shares of Class B Common Stock, (ii) any transfer, whether or not for value, (subject to certain exceptions set forth in the Issuer's amended and restated certificate of incorporation), or (iii) in the event of the death or permanent mental disability (as defined in the Issuer's amended and restated certificate of incorporation) of Mr. Keywell, shares of Class B Common Stock held by him or his permitted estate planning entities will convert to Class A Common Stock, provided that the conversion will be deferred for up to nine months following his death or permanent mental disability so long as exclusive voting control of his shares of Class B Common Stock is being exercised by another Class B stockholder.</footnote>
        <footnote id="F5">The shares of Class B Common Stock reported on this line are held by Rugger Ventures LLC, an entity owned by Mrs. Keywell (80%) and Mr. Keywell's children (20%).</footnote>
        <footnote id="F6">Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock.</footnote>
        <footnote id="F7">25% of the restricted stock units on this line will vest on June 19, 2013, and and the remaining restricted stock units will vest in 12 equal installments at the end of each quarter, beginning on September 19, 2013, subject to Mr. Keywell's continued service as a director of the Company through each vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David Schellhase, by power of attorney</signatureName>
        <signatureDate>2012-12-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
