The Castle School is a coeducational secondary school and sixth form with academy status, located in Thornbury, South Gloucestershire, England, which serves the town and the surrounding villages.

The school site on Park Road has seen additions in recent years including the community sports centre,[1] the Octagon Drama Studio[2][3] and in 2024 a new Post-16 Centre and a 20-classroom Maths and Science building.

[7] In 1962, during the headship of Mr Cliff J. Martin, plans were drawn up for a new building to house the expanding secondary school.

[8] Building work started the following year on Park Road, the site used as the school's playing field.

The official opening ceremony took place in 1966, attended by the Duke of Beaufort, Chancellor at the University of Bristol at the time.