linguistic grouping of North American Indian tribes speaking related languages within the Penutian (Penutian languages) family. They traditionally resided in what are now southeastern Washington, northeastern Oregon, and west-central Idaho, U.S., in the basin of the Columbia River and its tributaries. Major groups included the cayuse, Molala, Palouse (or Palus), Nez Percé, Tenino, Umatilla, Wallawalla, and Yakima.

The Sahaptin were typical Plateau Indians (Plateau Indian). The Plateau region lies between the Rocky Mountains and the coastal cordillera and is characterized by semiarid region of sagebrush, grass, and scattered pine groves that are interwoven with rivers and streams containing plentiful salmon and other fish. Thus, the Plateau peoples had an unusually reliable food supply for desert dwellers. They also hunted such game as deer and gathered a variety of wild plant foods.

The western Sahaptin tribes, including the Molala, Tenino, and Yakima, avoided formal political structures; the primary political unit was the autonomous village composed of a band of related families. These groups typically allied together during times of war and otherwise remained independent. The eastern tribes, including the Nez Percé, Palouse, Cayuse, and Umatilla, were heavily influenced by the Plains Indians (Plains Indian) with whom they traded on seasonal journeys across the Rockies. They developed relatively strong political cohesion for Plateau tribes, with a tribal chief and council; eastern Sahaptin families also tended to marry intertribally. Moreover, whereas the western groups tended toward pacifism, the eastern groups adopted many customs of Plains warfare, including graded war honours and communal victory celebrations and dances. The major foes of the Sahaptin were the Shoshone and Paiute to the south.

Traditional Sahaptin religious belief centred on guardian spirits (guardian spirit), whose existence was revealed in visions, and on shamanism. Shamans and medicine men (medicine man) and women were respected religious and social leaders.