Keiyo South is an electoral constituency in Kenya. It is one of four constituencies of Elgeyo-Marakwet County. The constituency has 6 wards, all of which elect Member of County Assembly (MCA) for Elgeyo Marakwet County which sits in the county Headquarters, Iten. The wards are namely: Metkei, Kabiemit, Chepkorio, Soy South and Soy North. The constituency was established for the 1969 elections. It was previously one of two constituencies of the former Keiyo District.