| Castle Rushen High School | |
| Coordinates: | 54.0744°N -4.6617°W |
| Motto: | Lhiat Myr Toilliu |
| Head: | Keith Winstanley |
| Address: | Arbory Road |
| City: | Castletown |
| Country: | Isle of Man |
| Postcode: | IM9 1RE |
| Enrolment: | c. 850 |
| Gender: | Co-educational |
| Lower Age: | 11 |
| Upper Age: | 19 |
| Houses: | Bradda Carrick Scarlett Langness |
| Colours: | Navy Light Blue |
Castle Rushen High School is a co-educational secondary state school located in Castletown on the Isle of Man for pupils from the south of the island.
See main article: Education in the Isle of Man. The Isle of Man has six secondary schools. The other comprehensive schools are St Ninian's High School, Ballakermeen High School, Ramsey Grammar School and Queen Elizabeth II High School. There is one private (fee-paying) school, King William's College.
The pupils of the school are grouped into four houses named after headlands or rocks in the south of the island: Bradda, Carrick, Langness and Scarlett. Houses compete in a number of events in the year ranging from sporting events such as inter-house rugby, cross country and netball to more academic competition in the form of a merit award system for good work. There are four trophies available each year for "Sport", "Merits", and "Attendance", and the overall best house trophy which is awarded to the house which does best over the other three categories.