Nyanchwa Adventist School, or ‘Nass’ as it was nicknamed, is a privately owned secondary school in Kisii. The school is located in Nyaribari Chache constituency in Kisii County.
It was established in 1912 by the Seventh Day Adventist Church, which set foot in the region through missionaries. The school is a mixed, day-only school. It is on the same compound with Nyanchwa Adventist College, with whom they also share a bus.