Montana state income tax — ITIN filer guide

Montana uses a graduated income tax from 4.7% to 5.65% (tax year 2026), administered by the Montana Department of Revenue. This guide covers who must file, how filing with an ITIN works, whether the state EITC applies to you, and when refunds arrive.

GRADUATED: 4.7% – 5.65% · 2 brackets

  • State return form: Form 2 (Montana Individual Income Tax Return)
  • Deadline (tax year 2026): April 15, 2027
  • Who must file: Must file if gross income exceeds the threshold for your filing status (tied to the standard deduction); exact dollar amounts on DOR's Individual Filing Requirements page — not captured this session.
  • State sales tax: none
  • Special regime: Long-term capital gains taxed at separate 3.0% / 4.1% rates with brackets aligned to ordinary-income brackets (HB 337). No state sales tax.
  • Scheduled change: HB 337: for TY2027 the top rate falls to 5.4% and the 4.7% bracket expands to $65,000 single / $130,000 MFJ (from $47,500 / $95,000 in 2026).

Montana refund timing

  • E-filed returns: DOR says it can take up to 90 days to issue a refund; e-filed returns enter processing immediately and move fastest with direct deposit.
  • Paper returns: Up to 90 days; paper returns are slower and first-time Montana filers may be sent a paper check for security reasons.
  • Check your Montana refund status

State tax agency

  • Montana Department of Revenue — revenue.mt.gov
  • Phone: (406) 444-6900
  • Free filing option: No state-run free e-file portal verified; IRS Direct File (which had served MT) will not be available from filing season 2026 onward — commercial software, Free File offers, or VITA.

Facts verified 2026-06-11 against official state sources (primary source). Figures refresh with every dataset review.

Filing with an ITIN

Your ITIN is fully accepted on the Montana state return — states accept the IRS-issued taxpayer number, the same one you use federally. The flow is always the same:

  1. Complete your federal return first (Form 1040 + ITIN)
  2. Transfer your federal figures to Form 2 (Montana Individual Income Tax Return)
  3. Apply state-specific deductions and credits
  4. E-file — No state-run free e-file portal verified; IRS Direct File (which had served MT) will not be available from filing season 2026 onward — commercial software, Free File offers, or VITA.
  5. Or visit a VITA site for free in-person preparation

Montana state EITC — do ITIN filers qualify?

The federal EITC requires valid SSNs for you, your spouse, and qualifying children — ITIN filers can never claim it. What varies is the STATE credit:

Montana Earned Income Tax Credit — 10% (rises to 20% of federal EITC beginning tax year 2026 per HB 337) of the federal EITC (refundable)

✗ SSN required (not available to ITIN filers)

DOR: you must qualify for the federal EITC to claim the Montana credit; the federal credit requires valid SSNs, so ITIN-only filers cannot claim it.

See how all 52 jurisdictions compare on the state tax hub and which tax credits ITIN filers can claim.

Last verified: 2026-06-11. Primary source: Montana Department of Revenue.

General procedural information for educational purposes. Not legal or tax advice. State tax rates change frequently — verify current figures with the state agency before filing. For case-specific guidance, consult a tax professional, enrolled agent, or CPA.