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

    <schemaVersion>X0204</schemaVersion>

    <documentType>3/A</documentType>

    <periodOfReport>2011-04-08</periodOfReport>

    <dateOfOriginalSubmission>2011-04-08</dateOfOriginalSubmission>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001512074</issuerCik>
        <issuerName>SCG Financial Acquisition Corp.</issuerName>
        <issuerTradingSymbol>SCGQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001300607</rptOwnerCik>
            <rptOwnerName>Sachs Gregory H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>615 N. WABASH AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO, President and Chairman</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001517761</rptOwnerCik>
            <rptOwnerName>Gergory H. Sachs Revocable Trust Dtd. April 24, 1998</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>615 N. WABASH AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1321905</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.50</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3200000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">182,857 shares of common stock beneficially owned by Reporting Person are subject to forfeiture in the event the underwriters of the initial public offering of the Issuer's securities do not exercise their over-allotment option.</footnote>
        <footnote id="F2">Gregory H. Sachs is the trustee and beneficiary of the Gregory H. Sachs Revocable Trust (the &quot;Trust&quot;) and is thereby the indirect holder of securities of the Issuer held by the Trust through its membership in SCG Financial Holdings LLC (the &quot;sponsor&quot;).  Gregory H. Sachs is the Manager of the sponsor and may be deemed to have beneficial ownership of all shares of common stock held by the sponsor.  Each Reporting Person disclaims beneficial ownership of any shares over which he or it does not have a pecuniary interest.</footnote>
        <footnote id="F3">The warrants will become exercisable on the later of 30 days after completion of Issuer's initial business combination (&quot;Business Combination&quot;) as described in the Issuer's prospectus relating to its initial public offering or April 18, 2012 and will expire five years after completion of the Business Combination.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Gregory H. Sachs</signatureName>
        <signatureDate>2012-02-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/Gregory H. Sachs, Trustee of Gregory H. Sachs Revocable Trust Dtd. April 24, 1998</signatureName>
        <signatureDate>2012-02-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
