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- Cambridge House Grammar School, Ballymena, County Antrim
- Campbell College, Belfast
- Carrickfergus Grammar School, Carrickfergus, County Antrim
- Christian Brothers' Grammar School, Omagh, County Tyrone
- Coleraine Academical Institution, Coleraine, County Londonderry
- Coleraine High School, Coleraine, County Londonderry
Read more about this topic: List Of Grammar Schools In Northern Ireland