The Cayuse are a Native American tribe in the state of Oregon in the United States. The Cayuse tribe shares a reservation and government in northeastern Oregon with the Umatilla and the Walla Walla tribes as part of the Confederated Tribes of the Umatilla Indian Reservation. The reservation is located near Pendleton, Oregon at the base of the Blue Mountains.
The Cayuse called themselves the Liksiyu in the Cayuse language. Originally located in present-day northeastern Oregon and southeastern Washington, they lived adjacent to territory occupied by the Nez Perce and had close associations with them. Like the Plains tribes, the Cayuse placed a high premium on warfare and were skilled horsemen. They developed the Cayuse pony. The Cayuse ceded most of their traditional territory to the United States in 1855 by treaty and moved to the Umatilla Reservation, where they have formed a confederated tribe.