The proportion of students eligible for free school meals is well above the national average.

[2] Hendon School now occupies the site where the 16th-century mapmaker John Norden lived, and only a pond survives from the park of Greenhill.

By 1927, the field at the back of the school was levelled and trees planted, and in 1929–1930 the building of the gymnasium was started.

In 1936 former pupil Harold Whitlock planted an oak tree sapling in front of the entrance to the gymnasium which he had received, along with his gold medal for the 50 kilometres (31 mi) walk, from Adolf Hitler at the Berlin Olympic Games.

In the late 1960s, when plans for the reorganisation of secondary education were passed by Parliament, the London Borough of Barnet suggested the amalgamation of Hendon County Grammar School, situated in Golders Rise, with St David's County Secondary School for Boys, in St David's Place, West Hendon.

Hendon Grammar School Choir released commercial recordings with Owen Brannigan, with traditional British songs.

In January 1964 it amalgamated with Brent Secondary Modern School on its site in Sturgess Avenue, West Hendon.

Extensions to the new buildings close to the perimeter on the south side of the site took place during the 1990s to provide extra room for the Maths and Music departments.