St. Paul H.S. School was begun as the boys' section of St. Raphael's H.S. School near Sat Prachar Press in 1956 with Sr. Ann as the principal and Fr. J. Partch as the in-charge. The first batch appeared in the H.S.S.C. Examination in 1962. 

In 1963, with the appointment of Fr. Wilhelm J. Lenzen as the first Principal, the boys' section was separated from St. Raphael's with its own recognition, identity and name. As the school grew up, the secondary section was separated and shifted to the new campus on the Boundary Road in 1975.

Ever since its inception, the school has had the privilege of the able leadership of eight Principals, eight Vice Principals and over 200 committed teachers. They were instrumental in moulding thousands of citizens, ranging in three generations, who are rendering their relentless service today in India and abroad as scholars, public servants, defence officers,doctors, engineers, industrialists, scientists, information technologists, philanthropists, journalists , etc. 
The school, which had been under the State Board from the beginning, was affiliated to the Central Board of Secondary Education, Delhi in 1996.