| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| CaomhÁN | - | Ancient Irish | ||
| Caratacos | - | Ancient Celtic | ||
| Caratacus | - | Ancient Celtic (Latinized) | ||
| Carlman | - | Ancient Germanic | ||
| Carloman | - | History, Ancient Germanic | ||
| Carolus | - | Ancient Germanic (Latinized) | ||
| Cassander | - | Ancient Greek (Latinized) | ||
| Cassia | KA-shə (English) | Ancient Roman | ||
| Cassian | KASH-ən (English) | Ancient Roman (Anglicized) | ||
| Cassianus | - | Ancient Roman | ||
| Cassius | KASH-əs (English), KAS-ee-əs (English) | Ancient Roman, English | ||
| Cathasach | - | Ancient Irish | ||
| Cato (1) | - | Ancient Roman | ||
| Celsus | - | Ancient Roman | ||
| Chares | - | Ancient Greek |