| Cipriano | | chee-pree-AH-no (Italian) | Italian, Spanish, Portuguese | |
| CirÍAco | | - | Portuguese, Spanish | |
| Ciriaco | | chee-ree-AH-ko (Italian), thee-ree-AH-ko (Spanish), see-ree-AH-ko (Latin American Spanish) | Italian, Spanish | |
| Ciril | | - | Slovene | |
| Cirila | | - | Slovene | |
| Cirino | | chee-REE-no (Italian), thee-REE-no (Spanish), see-REE-no (Latin American Spanish) | Italian, Spanish | |
| Ciro | | CHEE-ro (Italian), THEE-ro (Spanish), SEE-ro (Latin American Spanish) | Italian, Spanish | |
| Cissy | | SIS-ee | English | |
| Citra | | CHEET-rah | Indonesian | |
| ClÁUdia | | - | Portuguese | |
| ClÁUdio | | - | Portuguese | |
| ClÍDna | | - | Irish Mythology | |
| ClÍMaco | | - | Spanish | |
| ClÍOdhna | | KLEE-u-na | Irish, Irish Mythology | |
| ClÍOna | | - | Irish | |