| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Constant | kawn-STAWN (French), KAHN-stənt (English) | French, English (Rare) | ||
| Coreen | kə-REEN | English (Rare) | ||
| Coriander | KAWR-ee-an-dər | English (Rare) | ||
| Corynn | - | English (Rare) | ||
| Cree | KREE | English (Rare) | ||
| Creighton | KRAY-tən | English (Rare) | ||
| Crispin | KRIS-pin | English (Rare) | ||
| Crofton | KRAWF-tən | English (Rare) | ||
| Cuthbert | KUTH-burt | English (Rare) | ||
| Cyan | SIE-an | English (Rare) | ||
| Cybill | SIB-əl | English (Rare) | ||
| Cymone | see-MON | English (Rare) | ||
| Cyrilla | - | English (Rare) |