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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2012-03-27</periodOfReport>

    <dateOfOriginalSubmission>2012-04-04</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001431897</issuerCik>
        <issuerName>Annie's, Inc.</issuerName>
        <issuerTradingSymbol>BNNY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001545658</rptOwnerCik>
            <rptOwnerName>Bird Sarah</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ANNIE'S, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1610 FIFTH STREET</rptOwnerStreet2>
            <rptOwnerCity>BERKELEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94710</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP - Mktg &amp; Chief Mom Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Employee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>19.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2012-03-27</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13987</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-03-26</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13987</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13987</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person's original Form 4 erroneously stated the closing date of the issuer's IPO as the grant date rather than the effective date of the issuer's IPO registration statement.</footnote>
        <footnote id="F2">The number of shares was misstated in the reporting person's original Form 4 because of an error caused during calculations of the option's Black-Scholes value.</footnote>
        <footnote id="F3">Subject to the grantee's continued employment, the option vests at a rate of 25% of the total number of shares underlying the option on each anniversary of April 2, 2012, beginning on the second anniversary of April 2, 2012. The grantee's death or disability or a change in control of Annie's, Inc., as defined in the grant agreement, may also affect the vesting schedule.</footnote>
        <footnote id="F4">The expiration date was misstated in the reporting person's original Form 4 because it is directly related to the transaction date, which, as noted above, was misstated.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Stephen L. Palmer, as attorney-in-fact</signatureName>
        <signatureDate>2012-07-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
