| Ilarion | | - | Bulgarian, Macedonian | |
| Ilia | | eel-YAH (Russian) | Georgian, Russian, Bulgarian, Old Church Slavic | |
| Iliana | | - | Greek, Bulgarian | |
| Ilija | | - | Macedonian, Serbian, Croatian, Bulgarian | |
| Ilina | | - | Bulgarian, Macedonian | |
| Iliya | | - | Bulgarian | |
| Iliyana | | - | Bulgarian | |
| Ioan | | - | Romanian, Welsh, Bulgarian | |
| Ioana | | - | Romanian, Bulgarian | |
| Iordan | | - | Bulgarian | |
| Irina | | ee-REE-nah (Russian), EE-ree-nah (Finnish) | Russian, Bulgarian, Macedonian, Romanian, Finnish, Georgian | |
| Iskra | | - | Bulgarian, Macedonian, Croatian, Serbian | |
| Iva (1) | | - | Bulgarian, Serbian, Croatian, Macedonian | |
| Ivailo | | - | Bulgarian | |
| Ivan | | ee-VAHN (Russian, Ukrainian), IE-vən (English) | Russian, Bulgarian, Ukrainian, Belarusian, Serbian, Croatian, Czech, Slovak, Macedonian, Slovene, En | |