Shelby is a city in and the county seat of Toole County, Montana, United States. The population was 3,169 at the 2020 census.

Toole County is a county in the northern portion of the U.S. state of Montana. As of the 2020 census, the population was 4,971. Its county seat is Shelby. The county was established in 1914 from parts of Hill County and Teton County and was named after Joseph Toole, the first and fourth governor of Montana. Its northern boundary is the Canada–United States border south of Alberta.