St. Thomas Aquinas Senior High School is a Ghanaian public day senior high school for boys in the Osu district of Accra in the Greater Accra Region. It was established in 1952. The school is currently located in Cantonments, a suburb of Accra. It was established to provide education for boys of the Accra Archdiocese of the Catholic church whose parents could not afford the cost of sending their male children to expensive boarding schools.

Accra is the capital and largest city of Ghana, located on the southern coast at the Gulf of Guinea, which is part of the Atlantic Ocean. As of 2021 census, the Accra Metropolitan District, 20.4 km2 (7.9 sq mi), had a population of 284,124 inhabitants, and the larger Greater Accra Region, 3,245 km2 (1,253 sq mi), had a population of 5,455,692 inhabitants. In common usage, the name "Accra" often refers to the territory of the Accra Metropolitan District as it existed before 2008, when it covered 199.4 km2 (77.0 sq mi). This territory has since been split into 13 local government districts: 12 independent municipal districts and the reduced Accra Metropolitan District (20.4 km2), which is the only district within the capital to be granted city status. This territory of 199.4 km2 contained 1,782,150 inhabitants at the 2021 census, and serves as the capital of Ghana, while the district under the jurisdiction of the Accra Metropolitan Assembly proper (20.4 km2) is distinguished from the rest of the capital as the "City of Accra".