| Chlotichilda | | - | Ancient Germanic | |
| Chrysanthe | | - | Ancient Greek | |
| Chrysanthos | | - | Greek, Ancient Greek | |
| Cleisthenes | | KLIES-thə-neez (English) | Ancient Greek (Latinized) | |
| Cleitus | | - | Ancient Greek (Latinized) | |
| Cleon | | - | Ancient Greek (Latinized) | |
| Cleopatra | | klee-ə-PAT-rə (English) | Ancient Greek (Latinized) | |
| Clitus | | - | Ancient Greek (Latinized) | |
| Clodovicus | | - | Ancient Germanic (Latinized) | |
| Clothildis | | - | Ancient Germanic (Latinized) | |
| Clovis | | KLO-vis (English), klo-VEES (French) | Ancient Germanic (Latinized), French | |
| Colobert | | - | Ancient Germanic | |
| Conrad | | KAHN-rad (English), KAWN-raht (German) | English, German, Ancient Germanic | |
| Corinna | | kə-REEN-ə (English), kə-RIN-ə (English), ko-RI-nah (German) | English, German, Ancient Greek (Latinized) | |
| Cosmas | | - | Ancient Greek (Latinized) | |