St Mary's Secondary School is located at Clement Town, Dehradun
. It was established in 1950. The school is a branch of the Institute of the Franciscan Clarist Sisters of the Most Blessed Sacrament, started by Mother Seraphina, Italy. The school is affiliated to Central Board of Secondary Education, New Delhi
. The school mainly aims at developing the intellectual, moral, and spiritual strengths of the student. Classes up to the X standard are offered. The medium of instruction is English. Training is also provided in arts and craft, painting, computer science, cutting and tailoring, typing, music, and sports.