| Iolanda | | - | Italian, Portuguese, Romanian | |
| Ion (1) | | YON (Romanian) | Basque, Romanian | |
| Ionel | | yo-NEL | Romanian | |
| Ionela | | yo-NEL-ah | Romanian | |
| IonuȚ | | - | Romanian | |
| Iosephus | | - | Late Roman | |
| Iosif | | ee-O-seef (Russian), YO-seef (Romanian) | Russian, Romanian, Greek | |
| Iovianus | | - | Ancient Roman | |
| Iovis | | - | Roman Mythology | |
| Iovita | | - | Ancient Roman | |
| Irina | | ee-REE-nah (Russian), EE-ree-nah (Finnish) | Russian, Bulgarian, Macedonian, Romanian, Finnish, Georgian | |
| Isabela | | ee-sah-BEL-ah (Spanish) | Spanish, Portuguese, Romanian | |
| Isabella | | ee-zah-BEL-lah (Italian), iz-ə-BEL-ə (English) | Italian, German, English, Swedish, Norwegian, Danish, Dutch, Romanian | |
| Isaura | | ee-SOW-rah (Spanish) | Portuguese, Spanish, Late Roman | |
| Isaurus | | - | Late Roman | |