The school was established by the Mar Thoma Church Educational Society (MTCES) on June 6, 1966. It is located on a 30-acre (120,000 m2) campus, at Mukkolakkal, a village on the outskirts of Thiruvananthapuram city. Other institutions located on the same campus include St. Thomas Higher Secondary School, St. Thomas Teachers' Training College, St.Thomas Central School and St. Thomas Pre-primary School. The students of the St Thomas are popularly called Santhomites.