Grosvenor Grammar School was founded (as Grosvenor High School) in 1945 by the Belfast Corporation to cope with the increase in demand for grammar school education in the area. It was sited in Roden Street, off the Grosvenor Road, and remained there until 1958, when the present location was secured at Cameronian Drive in the east of the city.

Grosvenor Grammar School was founded (as Grosvenor High School) in 1945 by the Belfast Education Authority to cope with the increase in demand for grammar school education in the Greater Belfast area.  Whilst it had already been decided to acquire, by compulsory purchase, 20 acres of ground at Orangefield, accommodation was to be provided as a temporary measure at Grosvenor Public Elementary School in Roden Street, off the Grosvenor Road.  112 pupils were enrolled in Grosvenor in January 1945.  

Numbers increased gradually, especially after the introduction of the Qualifying Examination in 1947, so that by 1950 when the first Upper Sixth was established, the full range of grammar school year groups was complete and approximately 750 pupils attended instead of the anticipated maximum of 480.  As a result, from 1948-50 a branch of the school housing 150 boys and 5 members of staff was opened in Orangefield Primary School.  Sketches for the new school in Cameronian Drive, Orangefield, were seen for the first time in 1952 but progress was slow and it wasn’t until June 1958 that the move was made.  

Entry to the new state-of-the-art building (which cost £250,000 to build and furnish) in September 1958 was an adventure for many of the pupils who travelled on two buses across the city to get there.  On arrival at school, outdoor shoes had to be removed to be replaced by school regulation sandals in order to protect the new floor surfaces.  In the mid 1960s a new Science Block was added and a Sixth Form Centre erected, providing tutorial rooms, a study area, a lecture/drama room and a common room with kitchen/coffee bar; this building became the prototype for sixth form provision in Northern Ireland.

The catchment area of the school continued to expand to include most of Greater Belfast and North and Mid-Down and in order to avoid confusion with other non-grammar ‘High Schools’, the Board of Governors changed the name of the school to Grosvenor Grammar School in 1993.  As the decades wore on, however, and with the growth in pupil numbers, the expansion of the curriculum and the advance of technology, the lack of adequate and up-to-date accommodation became increasingly noticeable.  The opening of the £4.5m Ken Reid Science & Technology block in November 1999 addressed the shortcomings to some extent but it was never going to be enough.  As Phase 1 of a multi-phase plan, the new building was only a step on the path, a path which changed completely, however, when it was announced in 2004 that Grosvenor would be part of a major Public-Private-Partnership school-building project in Belfast.  

Finally, after many years of wrangling and negotiating, the new £18.5m (with a further £1.2m for Furniture and Equipment) Grosvenor Grammar School opened on 12 April 2010 on our 34 acre site off Marina Park. 

Under the leadership of its five Principals (Mr William Moles 1945-1972, Mr Ken Reid 1972-1993, Mr John Lockett 1993-2008, Mr Robin McLoughlin 2008-2014 and currently Dr Frances Vasey) the school has earned a well deserved reputation for very high standards of achievement, pastoral care, innovation in education and providing a wide range of opportunities for pupils from all backgrounds, the vast majority of whom pass on to universities throughout the British Isles.