| IgnÁC | | EEG-nahts (Hungarian) | Hungarian, Czech | |
| Ilona | | EE-lo-naw (Hungarian), ee-LO-nah (German), EE-lo-nah (Finnish) | Hungarian, German, Finnish, Latvian, Lithuanian, Polish, Czech | |
| Irena | | ee-RE-nah (Polish), ee-RAY-nah (Dutch) | Polish, Czech, Slovene, Croatian, Serbian, Dutch, Lithuanian | |
| Irenka | | ee-REN-kah (Polish) | Polish, Czech | |
| Iva (2) | | - | Czech, Slovak, Slovene | |
| Iva (3) | | - | Czech | |
| 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 | |
| Iveta | | - | Czech, Slovak | |
| Ivka | | - | Croatian, Bulgarian, Slovak, Czech | |
| Ivo (1) | | EE-vo (German, Dutch, Italian), EE-fo (German), EE-voo (Portuguese) | German, Dutch, Italian, Portuguese, Czech, Ancient Germanic | |
| Ivona | | - | Czech, Slovak, Croatian, Macedonian | |
| JÁChym | | - | Czech | |
| Jakub | | YAH-kuwp (Polish) | Polish, Czech, Slovak | |