How to Appeal Your Property Tax in Montana: Step-by-Step Guide for 2026
Montana’s Department of Revenue sets property values, and your county tax appeal board hears the first formal appeal. Either one, an AB-26 informal review or a county board appeal, has to be filed within 30 days from the date printed on your classification and appraisal notice to count for both years of the cycle; for homes and other class four property, a later filing can still cover the cycle’s second year (MCA 15-7-102, 15-15-102).
Montana appeal deadlines by step
| Step | Filed with | Deadline rule | Law |
|---|---|---|---|
| Informal review, Form AB-26 (optional) | Department of Revenue field office | 30 days from the date on the classification and appraisal notice; for class four property a later objection, due by June 1 of the cycle’s second year (or 30 days from the date on a notice received in that year), counts for that year only | 15-7-102(3)(a) |
| County tax appeal board, no AB-26 filed | County clerk and recorder | 30 days from the date on the classification and appraisal notice; for class four property a later appeal, due by June 1 of the cycle’s second year (or 30 days from the date on a notice received in that year), counts for that year only | 15-15-102(2), (3); 15-7-102(3)(a) |
| County tax appeal board after an AB-26 decision | County clerk and recorder | 30 days from the date on the department’s notice of its determination | 15-7-102(6) |
| Montana Tax Appeal Board | Montana Tax Appeal Board, form MTAB-801 | The later of 45 calendar days after the county board hearing or 30 calendar days after the county board mails its decision | 15-2-301(1)(b) |
| Judicial review | District court of the county where the property sits, or, at the taxpayer’s option, the First Judicial District | 60 days after service of the Montana Tax Appeal Board’s final decision | 15-2-303(2) |
The 30 days run from the date on the notice, not from the day it lands in your mailbox. The Montana Tax Appeal Board warns that the appraisal notice “is usually mailed in the June” and is not the county tax bill, which comes later. By the time the bill arrives, the window can be closed.
Homes are valued once per two-year cycle
Class four property, which includes land and single-family residences, is revalued every 2 years (15-7-111). The department’s appeals page says all property owners would receive a notice in 2025 for the 2025–2026 cycle, and that the valuation date for that cycle is January 1, 2024. The department asks for evidence tied to that date.
For class four property the statute gives a second chance within the same cycle. An objection filed within 30 days of the notice counts for both years. One filed later applies only to the second year, and it has to be in by June 1 of that second year, or, if you receive a new classification and appraisal notice during that second year, within 30 days from the date on that notice (15-7-102(3)(a)(ii)). For the current cycle the department set that date as June 1, 2026, with any change applying to tax year 2026 only. That June 1 date has now passed.
A county board takes one application per valuation cycle, and after an AB-26 decision you cannot file a second application for the same property in that cycle (15-15-102(3), (4)).
AB-26 is optional, not a required first step
The Department of Revenue says so on its own appeals page: “You can choose to appeal the classification or assessment values shown on your notice directly to your local county tax appeal board (CTAB) rather than using our informal review process.” Choosing AB-26 does not shorten the county board window: that 30-day clock runs from the date on the department’s notice of its determination (15-7-102(6)).
AB-26 (version V10 3/2026) can be submitted online through the department’s portal with a Montana Okta account, or on paper by email, mail or hand delivery to the field office for your county. The department lists what helps: your estimate of value as of January 1, 2024; a purchase price, fee appraisal, or comparable sales or listings within six months of that date; and a builder’s cost breakdown for a remodel or new construction.
What the department must do with your objection
- Consider an independent appraisal that meets the Montana board of real estate appraisers’ standards and was completed within 6 months of the valuation date, or tell you why it did not use it (15-7-102(3)(e)).
- For residential or commercial property, send its methodology and data sources within 8 weeks if you agree to confidentiality terms. Comparable sales and market-area sales data are released only after a signed confidentiality agreement (15-7-102(3)(b), (c)).
- Not set a value above the one you objected to, unless the increase comes from a physical change in the property or an error in the department’s property data (15-7-102(3)(f)).
At the county tax appeal board
The board is appointed by the county commissioners and is not part of the Department of Revenue. Its session runs from July 1 to December 31 of the tax year, with later meetings at its discretion (15-15-101(4)). Use form MTAB-401 and send the original plus one copy to the clerk and recorder; the clerk’s date stamp is the date of receipt (15-15-102(2)).
You or your agent must attend the hearing. Without attendance the board cannot grant a reduction and the road to the state board closes, unless the board waives attendance on your written request with the department’s written agreement (15-15-103(1)). The MTAB-401 form puts the burden on you: “The taxpayer has the burden to show how the DOR incorrectly valued the property.” If the county board refuses or fails to hear a timely application, it is considered granted the day after the board’s final meeting for the year, with exceptions listed in 15-15-103(2).
Montana Tax Appeal Board and district court
SB 328 (Chapter 206, Laws of 2025) changed the second-level deadline. It took effect on passage and approval and applies to appeals from county board hearings held on or after that date. The appeal is now due by the later of 45 calendar days after the hearing or 30 calendar days after the county board mails its decision. The Montana Tax Appeal Board’s own forms (MTAB-401 and MTAB-801) and its appeal-process page still describe the older rule of 30 days from when you received the decision. The statute controls, but the safest course is to have your appeal reach the state board within 30 days of the date the county board mailed its decision, which meets both.
For a class four residential appeal you may elect an informal review by the state board. That decision is final for both sides, with no appeal to district court (15-2-301(8)). In a residential valuation appeal before the state board, a qualifying independent appraisal “is presumed to establish assessed value” unless the department rebuts it (15-2-301(3)(b)). If the department takes a class four residential valuation case to court and the taxpayer substantially prevails, the court awards costs and reasonable attorney fees (15-2-303(6)).
Pay under protest or lose the refund
Filing does not pause the bill. Under 15-1-402(2), a person appealing “shall pay the tax or fee under protest when due in order to receive a refund.” Unpaid, the appeal can continue, but no tax can be refunded from it. The written protest goes to the county treasurer with the payment, and the protested amount is capped at the increase over last year’s tax unless your stated grounds support a different amount, such as a reappraisal change (15-1-402(1)).
Denials of the homestead or rental reduced tax rate follow their own path: an objection to the department within 30 days after the date of the denial notice, then the county board within 30 days from the date on the notice of the department’s determination (15-6-418). Rates and eligibility are covered in our Montana property tax guide.
More on property taxes in neighboring states
- Property tax calculator
- Idaho assessment appeals
- Wyoming assessment appeals
- North Dakota assessment appeals
- Moving to Missoula
FAQ
Do I have to file an AB-26 before going to the county board?
No. The department’s page says you can appeal directly to the county tax appeal board, filed with the clerk and recorder within 30 days from the date on your notice.
I missed the 30 days. Is the cycle lost?
For class four property, no. A late AB-26 objection, or an appeal filed directly with the county tax appeal board, can still cover the second year of the cycle if filed by June 1 of that year, or within 30 days from the date on a notice you receive in that second year (15-7-102(3)(a)(ii), 15-15-102(3)). For the 2025–2026 cycle the Department of Revenue set that date as June 1, 2026.
Can the department raise my value because I asked for a review?
Only for a physical change in the property or an error in its property data; otherwise the AB-26 result cannot exceed the value you objected to (15-7-102(3)(f)).
My property record lists the wrong square footage. Where do I fix it?
With the Department of Revenue. The Montana Tax Appeal Board says it has no appraisers and “cannot make changes on the property record card,” and the department’s appraiser can visit and correct it.
Can I appeal again next year within the same cycle?
Not to the county board. It accepts one application per valuation cycle, and an owner who went through AB-26 cannot file a second one for the same property in that cycle (15-15-102(3), (4)).