The Kittitas are a Sahaptin tribe closely related to the Yakama, sometimes described as a band or subtribe of the Yakama. Their traditional territories are found within Kittitas and Yakima counties within Washington state, chiefly in the Kittitas Valley, Naches Valley, Wenas Valley, and upper Yakima Valley. Individuals of Kittitas descent are today enrolled in the Confederated Tribes and Bands of the Yakima and the Confederated Tribes of the Colville Reservation, but the Kittitas are not recognized as a distinct band by either tribal government.

The Sahaptin are a number of Native American tribes who speak dialects of the Sahaptin language. The Sahaptin tribes inhabited territory along the Columbia River and its tributaries in the Pacific Northwest region of the United States. Sahaptin-speaking peoples included the Klickitat, Kittitas, Yakama, Wanapum, Palus, Lower Snake, Skinpah, Walla Walla, Umatilla, Tenino, and Nez Perce.