| Casimiro | | - | Spanish, Portuguese, Italian | |
| Cassandra | | kə-SAN-drə (English), kə-SAHN-drə (English), kahs-SAHN-drah (Italian) | English, Spanish, Portuguese, Italian, French, German, Greek Mythology (Latinized) | |
| Catarina | | kah-tah-REE-nah (Italian), ka-ta-REE-na (Galician) | Italian, Portuguese, Occitan, Galician | |
| Caterina | | - | Italian, Catalan | |
| Cecilia | | sə-SEE-lee-ə (English), sə-SEEL-yə (English), che-CHEE-lyah (Italian), the-THEE-lyah (Spanish), se-SEE-lyah (Latin American Spanish), se-SEEL-yah (Danish, Norwegian), SE-see-lee-ah (Finnish) | English, Italian, Spanish, Swedish, Danish, Norwegian, Finnish, Dutch, German | |
| Cecilio | | the-THEE-lyo (Spanish), se-SEE-lyo (Latin American Spanish), che-CHEE-lyo (Italian) | Spanish, Portuguese, Italian | |
| Celeste | | che-LE-ste (Italian), sə-LEST (English) | Italian, English | |
| Celestina | | the-le-STEE-nah (Spanish), se-le-STEE-nah (Latin American Spanish), che-le-STEE-nah (Italian) | Spanish, Italian | |
| Celestino | | the-le-STEE-no (Spanish), se-le-STEE-no (Latin American Spanish), che-le-STEE-no (Italian) | Spanish, Italian, Portuguese | |
| Celia | | SEEL-yə (English), SEE-lee-ə (English), THE-lyah (Spanish), SE-lyah (Latin American Spanish), CHE-lyah (Italian) | English, Spanish, Italian | |
| Celino | | che-LEE-no (Italian), the-LEE-no (Spanish), se-LEE-no (Latin American Spanish) | Italian (Rare), Spanish (Rare) | |
| Celio | | CHE-lyo (Italian), THE-lyo (Spanish), SE-lyo (Latin American Spanish), SE-lyoo (Portuguese) | Italian, Spanish, Portuguese | |
| Celso | | CHEL-so (Italian), THEL-so (Spanish), SEL-so (Latin American Spanish) | Italian, Spanish, Portuguese | |
| Cesare | | CHE-zah-re | Italian | |
| Cesarina | | che-sah-REE-nah | Italian | |