CLHS
- California Lutheran High School
- Canyon Lake High School (Texas)
- Cardinal Langley Roman Catholic High School
- Center Line High School
- Central Lafourche High School
- Central Lancaster High School
- Chung Ling High School
- Clear Lake High School (Clear Lake, Iowa)
- Clear Lake High School (Houston, Texas)
- Common Lisp HyperSpec
- Concordia Lutheran High School (Fort Wayne, Indiana)
- Concordia Lutheran High School (Texas)
- County Line High School
- Crean Lutheran High School
- Cypress Lake High School