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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-09-16</periodOfReport>

    <issuer>
        <issuerCik>0001516551</issuerCik>
        <issuerName>Skye Bioscience, Inc.</issuerName>
        <issuerTradingSymbol>SKYE</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001598549</rptOwnerCik>
            <rptOwnerName>Schwab Andrew J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O 5AM VENTURE MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>4 EMBARCADERO CENTER, SUITE 3110</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>32607</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.91</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>142463</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 5AM Ventures II, L.P.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1285</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.91</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5616</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 5AM Co-Investors II, L.P.</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>981269</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 5AM Ventures VII, L.P.</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $1.70 to $2.11 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
        <footnote id="F2">The securities are directly held by 5AM Ventures II, L.P. (&quot;Ventures II&quot;). 5AM Partners II, LLC (&quot;Partners II&quot;) is the sole general partner of Ventures II. The Reporting Person is a managing member of Partners II and may be deemed to have shared voting and investment
power over the shares beneficially owned by Ventures II. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F3">The securities are directly held by 5AM Co-Investors II, L.P. (&quot;Co-Investors II&quot;). Partners II is the sole general partner of Co-Investors II. The Reporting Person is a managing member of Partners II and may be deemed to have shared voting and investment power over the
shares beneficially owned by Co-Investors II. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F4">The securities are directly held by 5AM Ventures VII, L.P. (&quot;Ventures VII&quot;). 5AM Partners VII, LLC (&quot;Partners VII&quot;) is the sole general partner of Ventures VII. The Reporting Person is a managing member of Partners VII and may be deemed to have shared voting and
investment power over the shares beneficially owned by Ventures VII. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks>On August 24, 2026, the Issuer effected a 1-for-8 reverse stock split of its Common Stock, which is reflected in the Reporting Person's number of securities beneficially owned reported in this filing.</remarks>

    <ownerSignature>
        <signatureName>/s/ Andrew J. Schwab</signatureName>
        <signatureDate>2026-09-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
