Formerly Chatham House and Clarendon House; the two schools federated in 2009 and the federated school became a new converter Academy from January 2011. A formal proposal to merge was submitted in February 2013 and this was agreed in June 2013. Therefore the schools became one school as of 1st September 2013: Chatham & Clarendon Grammar School.

The school remains a selective grammar school and offers a unique combination, not offered anywhere else in Thanet: a co-educational environment with a significant core of single-sex teaching running from Year 7 through to Year 11, topped off with a mixed 6th Form.