<?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>0001690959</rptOwnerCik>
            <rptOwnerName>Resnick Joshua</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE BOSTON PLACE, SUITE 3900</rptOwnerStreet1>
            <rptOwnerStreet2>201 WASHINGTON STREET, SUITE 3900</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02108</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>2508279</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2508279</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By SV Life Sciences Fund IV, L.P.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <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>71211</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>71211</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By SV Life Sciences Fund IV Strategic Partners, L.P.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Received in exchange for 6,730,810 shares of KalVista Pharmaceuticals, Ltd. Series A Preferred Shares and 1,885,228 shares of Series B Preferred Shares 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 (the &quot;Reverse Stock Split&quot;). Prior to the Reverse Stock Split, the closing price of the Company's common stock was $0.67 per share.</footnote>
        <footnote id="F2">SV Life Sciences Fund IV Strategic Partners, L.P., a Delaware limited partnership, and (ii)  SV Life Sciences Fund IV, L.P., a Delaware limited partnership. The general partner of both SV Life Sciences Fund IV, L.P. and SV Life Sciences Fund IV Strategic Partners, L.P. (collectively, the &quot;Funds&quot;) is SV Life Sciences Fund IV (GP), L.P. The general partner of SV Life Sciences Fund IV (GP), L.P. is SVLSF IV, LLC. Both SV Life Sciences Fund IV (GP), L.P. and SVLS IV, LLC may be deemed to beneficially own the shares held by the Funds. SV Life Sciences Fund IV (GP), L.P. and SVLS IV, LLC may be deemed to beneficially own the shares held by the Funds. SV Life Sciences Fund IV (GP), L.P. and SVLS IV, LLC disclaim beneficial ownership of the shares held by the Funds except to the extent of any pecuniary interest therein. Dr. Resnick, a director of Issuer, is a partner of SV Life Sciences.</footnote>
        <footnote id="F3">Received in exchange for 191,091 shares of KalVista Pharmaceuticals, Ltd. Series A Preferred Shares and 53,523 shares of Series B Preferred Shares in connection with the closing of the Transaction. 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 Reverse Stock Split. Prior to the Reverse Stock Split, the closing price of the Company's common stock was $0.67 per share.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Joshua Resnick</signatureName>
        <signatureDate>2016-11-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
