It is run by the Diocese of Agra (Church of North India) and recognized by the Department of Education, Delhi.

It is affiliated to the Central Board of Secondary Education and prepares students for the All India Senior School Certificate Examination.

St. Thomas' School was founded in 1930 by an English missionary, Helen Jerwood, in Delhi at Mandir Marg and Karol Bagh.

The school encourages leadership skills and also introduces students to the democratic system of government.

The winter uniform is a full sleeves white blouse with a dark green and brown check skirt, a brownish mustard blazer with the school emblem, a full sleeves sweater of the same color as the blazer and green woolen socks.