For the college, see University of Montana - Western.

Western Montana is the western region of the state of Montana, United States.

Western Montana encompasses approximately the western third of the state roughly on a dividing line running north from Yellowstone National Park through Helena and Browning to the Canadian border. It includes the mountainous parts of Montana, including the Continental divide and the eastern slope of the Rocky Mountains. It also includes Glacier National Park, the Bob Marshall Wilderness Area, Flathead Lake, Anaconda, Butte, Missoula, Kalispell, Hamilton, and Whitefish.

It also includes the following counties: Lincoln, Flathead, Sanders, Missoula, Lake, Ravalli, Pondera, Deer Lodge, Powell, Silver Bow, Gallatin, Mineral, Teton, Glacier, Jefferson, Granite, Broadwater, Madison, Beaverhead County, and Lewis and Clark. The estimated population according to the US Census Bureau as of 2004 was 510,366 out of Montana's total estimated population of 926,865. One of Montana's smallest communities, Saltese (pop. 30), is located at I-90's Exit 10, just east of the Idaho border and Lookout Pass Ski Area. Missoula, Helena, Butte, Kalispell, and usually Bozeman are considered part of Western Montana.

Great Falls, while technically in the western half of the state, is usually considered to be part of Eastern Montana because it is east of the Rocky Mountains and is geographically and culturally similar to the eastern half of the state.