| Celestino | | the-le-STEE-no (Spanish), se-le-STEE-no (Latin American Spanish), che-le-STEE-no (Italian) | Spanish, Italian, Portuguese | |
| Celio | | CHE-lyo (Italian), THE-lyo (Spanish), SE-lyo (Latin American Spanish), SE-lyoo (Portuguese) | Italian, Spanish, Portuguese | |
| Celso | | CHEL-so (Italian), THEL-so (Spanish), SEL-so (Latin American Spanish) | Italian, Spanish, Portuguese | |
| CesÁRia | | - | Portuguese | |
| CesÁRio | | - | Portuguese | |
| CezÁRio | | - | Portuguese (Brazilian) | |
| Cezar | | - | Romanian, Portuguese (Brazilian) | |
| Chica | | SHEE-kə | Portuguese | |
| Chico | | SHEE-koo | Portuguese | |
| Cipriano | | chee-pree-AH-no (Italian) | Italian, Spanish, Portuguese | |
| CirÍAco | | - | Portuguese, Spanish | |
| ClÁUdia | | - | Portuguese | |
| ClÁUdio | | - | Portuguese | |
| Clara | | KLAH-rah (Italian, German, Spanish), KLER-ə (English), KLAR-ə (English) | Italian, German, Spanish, Portuguese, Catalan, Romanian, English, Swedish, Danish, Late Roman | |
| Clarissa | | klə-RIS-ə (English) | English, Italian, Portuguese, Spanish | |