The Achomawi were Native Americans who lived in northern California. They lived in the Pit River basin near Montgomery Creek in Shasta County to Goose Lake on the Oregon line. They were closely related to the Atsugewi.

The Achomawi spoke a language belonging to the Shastan stock of the Hokan group.

Like other Northern Californians, the Achomawi lived by hunting and gathering. They lived in small groups with no centralized political authority.

The Achomawi were estimated to have numbered 3,000 in 1770. In 1910 there were 985. According to the Census of 1930, the entire Shasta group numbered 844, and in 1937, 418 Pit River Indians were enumerated.