Marijuana is legal in Montana. The state voted to approve Initiative 190 in the 2020 election, allowing adults 21 and over to possess up to 1 ounce of cannabis (with no more than 8 grams being concentrate). However, recreational dispensaries are not currently open. Regulations are yet to be established by the Montana Department of Revenue. The law states that the state must start accepting license applications by January of 2022.

Medical marijuana was legalized in Montana under Initiative 148 in 2004, and later revised under Initiative 182 in 2016. Montana medical cardholders are legally allowed to possess one ounce of usable medical cannabis. Formerly, patients were required to name a cannabis provider and shop with that provider exclusively. That requirement was overturned with Senate Bill 265, and now cardholders may shop at any Montana dispensary.