| Circe | | SUR-see (English) | Greek Mythology (Latinized) | |
| ClÍDna | | - | Irish Mythology | |
| ClÍOdhna | | KLEE-u-na | Irish, Irish Mythology | |
| Clio | | KLEE-o (Italian) | Greek Mythology (Latinized), Italian | |
| Clotho | | - | Greek Mythology (Latinized) | |
| Clytemnestra | | klie-təm-NES-trə (English) | Greek Mythology (Latinized) | |
| Clytia | | - | Greek Mythology (Latinized) | |
| Coeus | | - | Greek Mythology (Latinized) | |
| Conall | | - | Irish, Scottish, Irish Mythology | |
| ConchÚR | | - | Irish, Irish Mythology | |
| Conchobhar | | - | Irish, Irish Mythology | |
| Concordia | | kən-KAWR-dee-ə (English) | Roman Mythology | |
| Conlaoch | | - | Irish Mythology | |
| Connla | | - | Irish Mythology | |
| Conor | | KAHN-ər (English) | Irish, English, Irish Mythology | |