| Clodovicus | | - | Ancient Germanic (Latinized) | |
| Cloe | | - | Spanish, Italian | |
| Cloelia | | - | Ancient Roman | |
| Cloelius | | - | Ancient Roman | |
| Clopas | | KLO-pəs (English) | Biblical | |
| Clothildis | | - | Ancient Germanic (Latinized) | |
| Clotho | | - | Greek Mythology (Latinized) | |
| Clotilde | | klo-TEELD (French) | French, Italian, Portuguese, Spanish | |
| Clover | | KLO-vər | English (Rare) | |
| Clovis | | KLO-vis (English), klo-VEES (French) | Ancient Germanic (Latinized), French | |
| Clytemnestra | | klie-təm-NES-trə (English) | Greek Mythology (Latinized) | |
| Clytia | | - | Greek Mythology (Latinized) | |
| Cnaeus | | - | Ancient Roman | |
| Coco | | KO-ko | Various | |
| Coeus | | - | Greek Mythology (Latinized) | |