| Cassia | | KA-shə (English) | Ancient Roman | |
| Cassian | | KASH-ən (English) | Ancient Roman (Anglicized) | |
| Cassianus | | - | Ancient Roman | |
| Cassiopea | | ka-see-ə-PEE-ə (English) | Greek Mythology (Latinized) | |
| Cassiopeia | | ka-see-ə-PEE-ə (English) | Greek Mythology (Latinized) | |
| Cassius | | KASH-əs (English), KAS-ee-əs (English) | Ancient Roman, English | |
| Castor | | KAS-tər (English) | Greek Mythology (Latinized) | |
| Catahecassa | | - | Native American, Shawnee | |
| Catalina | | kah-tah-LEE-nah | Spanish | |
| Catarina | | kah-tah-REE-nah (Italian), ka-ta-REE-na (Galician) | Italian, Portuguese, Occitan, Galician | |
| Cate | | KAYT | English (Rare) | |
| Cateline | | - | Medieval French | |
| Caterina | | - | Italian, Catalan | |
| Cathasach | | - | Ancient Irish | |
| Catherin | | KATH-ə-rin, KATH-rin | English (Rare) | |