Martinsdale is an unincorporated community and census-designated place in southeastern Meagher County, Montana, United States.

[3] The town was a station stop on the now-abandoned transcontinental main line of the Chicago, Milwaukee, St. Paul and Pacific Railroad ("the Milwaukee Road"), and is a community center for nearby ranches and farms.

Martinsdale was the home of the poet Grace Stone Coates, author of Black Cherries, Mead & Mangel-Wurzel, and Portulacas in the Wheat.

[4] Martinsdale is on Highway 294, just south of U.S. Route 12, and 36 miles (58 km) east of White Sulphur Springs, the Meagher county seat.

The name was after Martin Maginnis, Montana Territory's delegate to Congress, who assisted the town in getting a post office.