Hesper is an unincorporated community in western Yellowstone County, Montana, United States.

The name Hesper or Hesperus, is the evening star, and according to old mythology, the king of the western land.

The community is named after the Hesper Farm, founded by Ignatius Daniel O'Donnell.

[4] In its heyday, the depot in Hesper served as a hub for surrounding farms and ranchers in the area.

The community is home to the Yellowstone Boys and Girls Ranch and is now considered a subdivision of the Billings Metro Area.