HELENA — Governor Greg Gianforte, R-Montana, has signed into law two highly debated bills affecting transgender Montanans. As of Thursday, Montanans must now use the bathroom that aligns with their sex at birth.

House Bill 121 requires public schools, correctional facilities, other public buildings – including the State Capitol – and domestic violence shelters to designate bathrooms, changing rooms and sleeping areas for either men or women, based on their biological sex at birth.

The law also requires those facilities to “take reasonable steps” to keep the opposite sex out. Someone could then sue a facility if they failed to take those steps and someone of the opposite sex used the space.

Opponents of HB 121 said it discriminates against transgender Montanans, while supporters of the law said it was about protecting women and girls.

““Standing alongside our partners in Montana and across the country, I am proud to safeguard privacy and security for women and girls – because a man shouldn’t be in a women’s restroom, shouldn’t be in a women’s shower room, and shouldn’t be housed in a women’s prison,” Gov. Gianforte said. “Today, we’re maintaining equal opportunity for all Americans, while also protecting women and girls and their right to safe and separate facilities and activities.”

Montana House Minority Leader Katie Sullivan, D-Missoula, expressed disapproval with the new laws and the Republican efforts this legislative session.

“The Governor told us he was going to clean up his property tax crisis this year and make it a priority. He gave himself a mid-February deadline to deliver that— It’s almost April. The Republican Governor has failed to deliver on taxes, and by his own metric. Yet, he's proud to enact new laws on toilets,” said Sullivan. “Gianforte and Republicans in the legislature have their minds in the gutter. Democrats have our minds on lowering taxes, funding public schools, and fixing healthcare. Democrats know Montanans can go to the bathroom without the government getting involved.”

HB 121, sponsored by Kerri Seekins-Crowe, R-Billings, goes into effect immediately.

The ACLU of Montana quickly filed a legal challenge to HB 121 on behalf of five plaintiffs, hours after Gianforte signed the legislation into law.

The lawsuit filed in Missoula County District Court on Thursday alleges that HB 121 violates numerous constitutional provisions, including the right to privacy and equal protection.

ACLU of Montana has requested an immediate preliminary injunction against the law.

On Thursday, Gianforte also signed House Bill 300 into law.

HB 300, also sponsored by Seekins-Crowe, amends Montana’s code to define allowing a biological male to compete in women’s and girls’ sports or use women’s or girls’ locker rooms as an act of discrimination toward female athletes.

The bill effectively bans transgender individuals from competing in those activities, both K-12 and college.

HB 300 is set to go into effect on October 1, 2025.

Both HB 121 and HB 300 passed through the legislature on party-line votes, with Republicans in favor and Democrats opposed.

Editor's note: This article has been updated with more information about a legal challenge from the ACLU of Montana against HB 121.