The 1950s to 1970s marked a period of expansion and development for the school beyond its original structure as new buildings were constructed to meet the growing number of pupils.

From the late 1950s until 1972, the first two years of the school were housed in classrooms at Carew Manor, half a mile away in Beddington Park.

In 1997, an old boy of WCGS, Chris Woodhead who was then HM Chief Inspector of Schools, opened a new science block.

It was later determined by an inquest that Ottun was pushed into Shawnigan Lake, Vancouver Island by a fellow student.

[8] WCGS joined the Folio Education Trust[9] during the administration of Jonathan Wilden, whereupon he assumed the title of "Executive Headteacher" for the schools comprising the Trust, with Jamie Bean having since taken over local control as the acting headmaster of the school.

[10] Academic performance at Wallington County Grammar School is outstanding, with students entering WCGS with very high levels of attainment.

In the latest Ofsted report from 2017, WCGS was rated 'outstanding' in all areas, including Achievement, Behaviour and Safety of pupils; Quality of teaching, learning and assessment; Personal development and Welfare; 16 to 19 study programmes; and Leadership and Management.