Gov. Greg Gianforte stood at the Capitol on Tuesday, September 8, to announce his backing of a public education campaign aimed at building support for a flat 4.7% state income tax, as first reported by Montana Free Press (montanafreepress.org). The governor wants the 2027 Legislature to send him a flat-tax bill, calling the proposal a top priority for his administration.

The Proposal

The campaign, branded “Flat. Fair. Montana.” and organized by the Mountain States Policy Center, would replace Montana’s current two-bracket income tax structure with a single 4.7% rate. Jack Baum of Americans for Tax Reform and Chris Cargill of Mountain States Policy Center joined Gianforte at the press conference. Representatives from the Frontier Institute and Americans for Prosperity-Montana also attended, with AFP-Montana deputy state director Henry Kriegel pledging his organization’s support.

Gianforte’s team has not yet drafted legislation, but the governor has been vocal about the goal since at least February 2026. “Montanans know how to spend their money better than the government does,” he told the Montana Free Press at Tuesday’s event.

How Montana Got Here

When Gianforte took office in 2021, Montana had seven income tax brackets with a top rate of 6.9%. Over his tenure, he reduced that to two brackets. A bill passed during the 2025 legislative session scheduled the top rate to fall from 5.9% to 5.4% by 2027. The proposed flat rate of 4.7% — which already applies to the lower bracket — would not change the tax burden for single filers with taxable income under $65,000 in 2027.

Montana is one of five states without a statewide sales tax. Eight states have no income tax at all, while 15 states already use a flat income tax structure.

Legislative Landscape

The proposal has drawn early support from Republican legislative leaders. House Speaker Brandon Ler has said House Republicans are prepared to act, and a handful of Senate Republicans announced backing for a flat tax in July. The 2027 Legislature, which convenes in January of that year, would be the vehicle for any legislation.

The Legislative Fiscal Division estimated that a 4.7% flat tax taking effect in 2028 would reduce state revenues by $140 million over the 2029 biennium.

Critics Push Back

Not everyone at the Capitol shares the governor’s enthusiasm. Rose Bender of the Montana Budget and Policy Center argued the cut would primarily benefit the wealthiest 5% of earners. Rep. Mark Thane and Sen. Dave Fern also criticized the plan, contending it amounts to a tax break for high-income Montanans that could put public services at risk.

Gianforte has maintained that reducing the tax burden encourages economic growth and investment in the state.