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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-11-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001348911</issuerCik>
        <issuerName>KalVista Pharmaceuticals, Inc.</issuerName>
        <issuerTradingSymbol>KALV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001185039</rptOwnerCik>
            <rptOwnerName>ALDRICH RICHARD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LONGWOOD CAPITAL</rptOwnerStreet1>
            <rptOwnerStreet2>PRUDENTIAL TOWER, 800 ROYLSTON STREET, S</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02199</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>2016-11-21</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>369419</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>369419</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Longwood Fund II LP</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Received in exchange for 1,268,971 shares of KalVista Pharmaceuticals, Ltd. Series B Preferred Stock in connection with the closing of the share purchase transaction (the &quot;Transaction&quot;) whereby KalVista Pharmaceuticals, Ltd. became a wholly-owned subsidiary of Carbylan Therapeutics, Inc., which changed its name to KalVista Pharmaceuticals, Inc. (the &quot;Company&quot;). On the effective date of the Transaction, the closing price of the Company's common stock was $9.38 per share. All numbers give effect to the 14:1 reverse stock split effected by the Company on November 21, 2016. Prior to the reverse stock split, the closing price of the Company's common stock was $0.67 per share.</footnote>
        <footnote id="F2">Longwood Fund II, LP, a Delaware limited partnership. Longwood Fund II GP, LLC (the &quot;Fund II General Partner&quot;) is the general partner of Longwood Fund II, L.P. and exercises voting and investment power with respect to securities owned directly by Longwood Fund II, L.P. Longwood Fund II, L.P. is managed by Longwood Fund Management, LLC. Mr. Aldrich is a managing member of Longwood Fund Management LLC who disclaims beneficial ownership of the shares held by Longwood Fund II, L.P. except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard Aldrich</signatureName>
        <signatureDate>2016-11-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
