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Montana Individual Income Tax Filing deadlines and extensions for 2025.
If you are a resident or have been involved in significant business operations within Montana, then you might be required to file Montana State Taxes. We look at the most important tax deadlines and tax extensions for Montana in 2025.
If your clients are residents or have been involved in significant business operations within Montana, then they might be required to file Montana State Taxes. This guide outlines the most important tax deadlines and tax extensions for Montana in 2025.
Montana C Corporation Tax Deadlines for 2025
You must file and pay Corporate Income Taxes in Montana by April 15, 2026.
Extension to File Taxes in Montana for 2025
The Extension Deadline for Montana corporate income tax returns is November 15, 2026.
Montana automatically grants a six-month extension for filing corporate income tax returns. This means you do not need to file for an extension in Montana.
This is an extension to FILE, not an extension to PAY – payment is still due April 15, 2026.
Montana S Corporation & Partnership Tax Deadlines for 2025
You must file in Montana by March 15, 2026.
Extension to File S Corporation & Partnership Taxes in Montana for 2025
The Extension Deadline for Montana S Corporation & Partnership income tax returns is September 15, 2026.
Montana automatically grants a six-month extension on filing pass-through entity tax returns. This means you do not need to file for an extension in Montana.
This is an extension to FILE, not an extension to PAY – payment is still due March 15, 2026.
Estimated Tax Deadline for Montana 2025
Estimated tax payments are due:
See Form IT instructions for the amount to pay with each voucher.
Individual Tax Deadline for Montana 2025
You must file and pay Individual Income Taxes in Montana by April 15, 2026.
Extension to File Taxes in Montana for 2025
The Extension Deadline for Montana individual income tax returns is October 15, 2026.
Montana automatically grants a six-month extension on filing personal income taxes. This means you do not need to file for an extension in Montana.
This is an extension to FILE, not an extension to PAY – payment is still due April 15, 2026.
Montana does not have an Estate Tax.
If at least 2/3 of your gross income for the taxable year is derived from farming, you may pay estimated tax at any time on or before January 15, 2026. If you wait until January 15, 2026, you must pay the entire balance of the estimated tax. However, if farmers file their tax return on or before March 1, 2026 and pay the total tax at that time, they need not file estimated tax.
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The material discussed on this page is meant for general illustration and/or informational purposes only and is not to be construed as investment, tax, or legal advice. You must exercise your own independent professional judgment, recognizing that advice should not be based on unreasonable factual or legal assumptions or unreasonably rely upon representations of the client or others. Further, any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.
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