Chailey Secondary School opened in April 1958, is a comprehensive secondary school located in the village of South Chailey, Chailey, just outside Lewes in East Sussex, UK. Chailey School was awarded specialist Language College Status in July 2002. In the year 2007, the school was also awarded Humanities College status. The school also provides adult classes in French, Italian, and Spanish. It does not have a sixth form.

In recent years the school has been substantially rebuilt, with little of the old buildings remaining.

In 2007 at least 99% of students acquired one GCSE at grades A*–G and in 2009, 82% of students achieved 5 or more A*–C grades with 72% achieving 5 or more including English and maths. The school academic program spans a range of disciplines including arts, sciences or humanities.

The current head teacher is Helen Key. She has been headteacher from 2016 to 2025.

In 2008 it celebrated its 50th anniversary since opening as a secondary modern in 1958. On 6 June 2008, The Duchess of Gloucester visited the school to attend a citizenship ceremony, the first of its kind to be held in a school with students present. This was to coincide with the school's 50th anniversary.