Caterham was founded in 1811, in Lewisham, by the Rev. John Townsend to provide a boarding education for the sons of Congregationalist ministers. Logically it was named the Congregational School. By 1884, the School had outgrown its premises, and the 114 boys with their teaching staff moved to the present Surrey site. In 1890, Caterham opened its doors to the sons of laymen and to day boys.
In 1995, after 184 years as a boys' day and boarding school, it merged with Eothen School for Girls to create a new independent co-educational foundation. Girls have been coming to Caterham for Sixth Form education since 1981, but the merger integrated the schools and enabled co-education to be offered to pupils aged 3 years and upwards.