Updated January 2025 · 5 min read
Key Montana Tax Deadlines
Never miss a Montana tax deadline again.
Individual & pass-through dates
Montana individual income tax returns (Form 2) follow the April 15 deadline, but quarterly estimated payments hit April 15, June 15, September 15, and January 15.
S-corporations and partnerships file by March 15. Submit Form PL-SSN to keep ownership data current even if there's no tax due.
Payroll and withholding schedule
Semi-weekly depositors remit within 3 business days after payday. Monthly depositors remit by the 15th of the following month. File Form MW-3 annually with W-2/W-3 reconciliations.
Set up TAP.gov.mt reminders for each entity. Missing a payroll deposit adds penalties quickly, especially for seasonal tourism employers.
Property & specialty taxes
Business equipment reports (Form AB-26) are due March 1. Residential property taxes hit November 30 and May 31 installments.
Oil, gas, and severance taxes have industry-specific calendars—work with a specialist if you have royalty or mineral revenue.