2027 Mississippi Tax Deadlines

Last updated: August 5, 2026

Key Mississippi tax dates at a glance

This block is the single date reference for 2027 Mississippi filing, payment, estimated-payment, and extension planning.

• March 15, 2028: S Corporation and Partnership Form 84-105 returns and payments due for calendar-year filers.
• April 15, 2027: First Mississippi estimated Individual income tax payment due.
• June 15, 2027: Second Mississippi estimated Individual income tax payment due.
• September 15, 2027: Third Mississippi estimated Individual income tax payment due.
• January 18, 2028: Fourth Mississippi estimated Individual income tax payment due.
• April 18, 2028: Mississippi C Corporation Form 83-105, Individual Forms 80-105 and 80-205, and balances due for calendar-year filers.
• September 15, 2028: Extended Mississippi S Corporation and Partnership returns due; payment is not extended.
• October 16, 2028: Extended Mississippi C Corporation and Individual returns due; payment is not extended.

When are Mississippi taxes due in 2027?

Mississippi 2027 calendar-year S Corporation and Partnership returns are generally due March 15, 2028, while C Corporation and Individual returns are due April 18, 2028. Estimated payments and filing-only extensions should be tracked separately by taxpayer type.

When are Mississippi C Corporation taxes due for 2027?

Mississippi C Corporations file Form 83-105, Mississippi Corporation Income Tax Return, and pay by April 18, 2028. The extended filing deadline is October 16, 2028; Form 83-180 is used when a Mississippi extension is needed without a federal extension, and payment remains due April 18, 2028.

• Complete Form 83-105, Mississippi Corporation Income Tax Return.
• Use Mississippi Taxpayer Access Point, or TAP, for eligible filing and payment.
• Pay the expected balance by April 18, 2028.
• Postmark permitted paper submissions by the due date.
• File and pay through Mississippi TAP.

When are Mississippi S Corporation and Partnership taxes due for 2027?

Mississippi S Corporations and Partnerships generally file Form 84-105 by March 15, 2028. Mississippi grants a six-month extension to September 15, 2028, but payment remains due March 15, 2028.

• Form 84-105: Pass-Through Entity Return for an S Corporation.
• Form 84-105: Pass-Through Entity Return for a Partnership.

When are Mississippi Individual taxes due for 2027?

A Mississippi Individual return is due April 18, 2028. Residents file Form 80-105, nonresidents file Form 80-205, and the extended filing deadline is October 16, 2028. Payment remains due April 18, 2028.

• Form 80-105: Mississippi Resident Individual Income Tax Return.
• Form 80-205: Mississippi Nonresident Individual Income Tax Return.

For 2027, Mississippi taxes the first $10,000 of taxable income at 0% and taxable income above $10,000 at 3.75%.

When are Mississippi estimated payments due?

Calendar-year Mississippi estimated payments are due on this schedule:

• April 15, 2027.
• June 15, 2027.
• September 15, 2027.
• January 18, 2028.

Who must make Mississippi estimated payments?

Taxpayers who expect a Mississippi income-tax balance after withholding and credits may need estimated payments. Apply the tax-year 2027 threshold, safe-harbor, and voucher instructions when the filing-year guidance is released.

What Mississippi rules should tax professionals watch for 2027?

• Mississippi does not allow an Individual deduction for federal income taxes paid.
• Retirement-friendly provisions may exempt Social Security benefits, military retirement pay, and qualifying pension income.
• Agriculture and rural items include agricultural land use assessment programs, beginning farmer credits, agricultural equipment sales tax exemptions, timber and forestry provisions, and rural development incentives.
• Business incentives include Advantage Mississippi Initiative, Jobs Tax Credit, Investment Tax Credit, Research and Development Credit, and Small Business Job Protection Act benefits.
• Energy, natural resources, manufacturing, tourism, gaming, hotel, restaurant, and entertainment-industry provisions should be checked against current Mississippi guidance before filing.

Tax-professional context: Several considerations shape Mississippi's 2027 tax landscape. Mississippi is phasing its individual income tax toward a flat rate — for 2027, the first $10,000 of taxable income is taxed at 0% and taxable income above $10,000 at 3.75%, with the rate scheduled to keep stepping down under enacted law. Electronic filing through Mississippi TAP continues to expand, and the state offers targeted planning opportunities for specific industries and activities.

Mississippi's phase-down toward a lower flat rate rewards year-specific review, which firms can source through the accounting firm directory.

What sources support these Mississippi deadlines?

• Mississippi Department of Revenue.
• Mississippi Individual Income Tax.
• Mississippi Corporate Income and Franchise Tax.
• Mississippi Form Search.

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