Alliance Girls' High School (AGHS) is a public national boarding school for girls located near the small town of Kikuyu in the Kiambu District of the Central Province of Kenya, 20 km from Nairobi. Founded in 1948 as the African Girls High School, it is within walking distance from its brother school Alliance High School.

Founded in 1948 by the Alliance of Protestant Missions, Alliance Girls' High School was the first institution of higher secondary education for African girls in Kenya, and served in parallel with Kenya High School which at that time only admitted European girls. Before Kenyan independence it was called African Girls High School. Alliance Girls High School sits on 71 acres of land in Kiambu West district, Central Province, originally donated by the Presbyterian Church of East Africa.