Sells is an unincorporated community and census-designated place (CDP) in Pima County, Arizona, United States. The population was 2,799 at the 2000 census. It is the capital of the Tohono O'odham Nation and the home of several of their tribal businesses, such as Tohono O'Odham Ki:Ki Association. Originally named Indian Oasis, by cattle-ranchers/businessmen brothers, Joseph and Louis Ménager in 1912. The Ménager brothers also built and ran the Indian Oasis Mercantile Store. The settlement took its present English name in 1918 to honor Indian Commissioner Cato Sells. The O'odham name means "Tortoise Got Wedged".

Pima County is a county in the south central region of the U.S. state of Arizona. As of the 2020 census, the population was 1,043,433, making it Arizona's second-most populous county. The county seat is Tucson, where most of the population is centered. The county is named after the Pima Native Americans, also known as Tohono O'odham, who are indigenous to this area.