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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2019-01-02</periodOfReport>

    <dateOfOriginalSubmission>2019-01-03</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001512931</issuerCik>
        <issuerName>MONROE CAPITAL Corp</issuerName>
        <issuerTradingSymbol>MRCC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001135079</rptOwnerCik>
            <rptOwnerName>RUBIN ROBERT S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MONROE CAPITAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>311 SOUTH WACKER DRIVE, SUITE 6400</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.6979</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>31712.367</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>In Partnership By Cousins, LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-01-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.65</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33212.367</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>In Partnership By Cousins, LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.65 to $9.78, inclusive. The reporting person undertakes to provide to Monroe Capital Corporation, any security holder of Monroe Capital Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares and prices at which the transaction was effected.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.57 to $9.69, inclusive. The reporting person undertakes to provide to Monroe Capital Corporation, any security holder of Monroe Capital Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares and prices at which the transaction was effected.</footnote>
        <footnote id="F3">Includes shares acquired through the Dividend Reinvestment Plan. This Form 4/A amends the Form 4 filed January 3, 2019 to correct the number of shares beneficially owned following the reported transactions, by including shares acquired through the Dividend Reinvestment Plan that were inadvertently omitted.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Robert S. Rubin by Nelson Mullins Riley &amp; Scarborough LLP with Power of Attorney</signatureName>
        <signatureDate>2019-03-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
