The school was started on April 12, 1982, as a primary school from nursery to class five with a staff of twelve members. Located in three bungalows in sector eight, arrangements were later made in sectors nine and eleven until land was allotted in Sector 45 by the UT Administration. When the first batch of Class ten graduated in 1988, the school was upgraded to senior secondary level in 1997.In October 2010, Camilla, Duchess of Cornwall, from the United Kingdom, visited the school and viewed an exhibition of models on environmental issues and another about festivals and cuisine, which was organised by the UK-India Education and Research Initiative (UKIERI). She also spoke to students at Park View Academy in Haringey, London, which was twinned with St. Stephen's, via a video link.At present, the school is housed in its own four-story building with over 3000 students and 165 staff members.