| Cleto | | KLE-to (Italian, Spanish) | Italian, Spanish, Portuguese | |
| Cloe | | - | Spanish, Italian | |
| Clotilde | | klo-TEELD (French) | French, Italian, Portuguese, Spanish | |
| ConcepciÓN | | kawn-thep-THYON (Spanish), kawn-sep-SYON (Latin American Spanish) | Spanish | |
| Concha | | KON-chah | Spanish | |
| Conchita | | kon-CHEE-tah | Spanish | |
| Conrado | | kon-RAH-dho | Spanish | |
| Constanza | | kon-STAHN-thah (Spanish), kon-STAHN-sah (Latin American Spanish) | Spanish | |
| Consuela | | kon-SWE-lah | Spanish | |
| Consuelo | | kon-SWE-lo | Spanish | |
| Coral | | KAWR-əl (English) | English, Spanish | |
| Cornelio | | kor-NE-lyo | Spanish, Italian | |
| Corona | | - | Late Roman, Italian, Spanish | |
| Crescencia | | - | Spanish | |
| CristÓBal | | kree-STO-bahl | Spanish | |