| Igor | | EE-gər (Russian), EE-gawr (Polish) | Russian, Polish, Slovene, Croatian, Serbian, Macedonian | |
| Ilija | | - | Macedonian, Serbian, Croatian, Bulgarian | |
| Ilinka | | - | Macedonian, Serbian, Croatian | |
| Irena | | ee-RE-nah (Polish), ee-RAY-nah (Dutch) | Polish, Czech, Slovene, Croatian, Serbian, Dutch, Lithuanian | |
| Isaija | | - | Serbian, Macedonian | |
| Isidora | | ee-see-DHO-rah (Spanish), ee-zee-DO-rah (Italian), iz-i-DAWR-ə (English) | Serbian, Macedonian, Spanish, Portuguese, Russian (Rare), Italian (Rare), English (Rare), Ancient Gr | |
| Iskra | | - | Bulgarian, Macedonian, Croatian, Serbian | |
| Iva (1) | | - | Bulgarian, Serbian, Croatian, Macedonian | |
| Ivan | | ee-VAHN (Russian, Ukrainian), IE-vən (English) | Russian, Bulgarian, Ukrainian, Belarusian, Serbian, Croatian, Czech, Slovak, Macedonian, Slovene, En | |
| Ivana | | - | Czech, Slovak, Serbian, Croatian, Slovene, Bulgarian, Macedonian | |
| Ivanka | | - | Bulgarian, Czech, Slovak, Serbian, Croatian, Slovene | |
| Ivica | | - | Croatian, Serbian | |
| Ivo (2) | | - | Bulgarian, Serbian, Croatian, Macedonian | |