Etoi Ki, or I'itoi kiꞌ in O'odham, is a mountain in southern Arizona on the Tohono O'odham Indian Reservation. West of Kitt Peak National Observatory and northwest of Sells, it rises beside Arizona State Route 86 across from Bird Nest Hill, about 62 miles west of Tucson and 24 miles north of the Mexican border. Part of the desert landscape of Pima County, it stands out as a distinct landmark along a main route through a sparsely settled stretch of the reservation.