Mosiro is an extinct Nilo-Saharan language spoken in the Arusha Region of Tanzania. It was the primary language of the hunter-gatherer Mosiro. It is classified as a variety of Ogiek by Rottland (1982) and Sommer (1992), but is assimilated to Nandi. Like other hunter-gatherers in the area, the Mosiro are called derogatory Dorobo (Ndorobo).