St.Thomas College designs and implements its own curriculum and tries to ensure that the students and the teachers have as much flexibility as possible to foster true learning in a child. St.Thomas College is affiliated to the Council for the Indian School Certificate Examination (CISCE). English is the medium of instruction, and the Council administers two public examinations - The Indian Certificate of Secondary Education (ICSE) at the end of year X and, subsequently, the Indian School Certificate (ISC) at the end of year XII. Both examinations are held annually in March.