| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Cassian | KASH-ən (English) | Ancient Roman (Anglicized) | ||
| Cassianus | - | Ancient Roman | ||
| Cassius | KASH-əs (English), KAS-ee-əs (English) | Ancient Roman, English | ||
| Catina | - | Romanian | ||
| Cato (1) | - | Ancient Roman | ||
| Celsus | - | Ancient Roman | ||
| Ceres | - | Roman Mythology | ||
| Cezar | - | Romanian, Portuguese (Brazilian) | ||
| Christiana | kris-tee-AN-ə (English) | English, Late Roman | ||
| Christianus | - | Late Roman | ||
| Christophorus | - | Late Roman | ||
| Cicero | SIS-ə-ro (English) | Ancient Roman | ||
| Ciprian | cheep-RYAHN | Romanian | ||
| Clara | KLAH-rah (Italian, German, Spanish), KLER-ə (English), KLAR-ə (English) | Italian, German, Spanish, Portuguese, Catalan, Romanian, English, Swedish, Danish, Late Roman | ||
| Claritia | - | Late Roman |