| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Iantha | - | Various | ||
| Ignatiy | - | Russian | ||
| Igor | EE-gər (Russian), EE-gawr (Polish) | Russian, Polish, Slovene, Croatian, Serbian, Macedonian | ||
| Ihar | EE-khahr | Belarusian | ||
| Ilari | EE-lah-ree (Finnish) | Russian, Finnish | ||
| Ilia | eel-YAH (Russian) | Georgian, Russian, Bulgarian, Old Church Slavic | ||
| Illarion | - | Russian | ||
| Ilya | eel-YAH | Russian | ||
| Inga | ING-ah (Swedish), ING-gah (German), EEN-gah (Russian) | Swedish, Danish, Norwegian, Icelandic, Latvian, Lithuanian, German, Russian, Ancient Scandinavian, A | ||
| Inna | EE-nah (Russian) | Russian, Ukrainian | ||
| Innokenti | - | Russian | ||
| Innokentiy | - | Russian | ||
| Innokenty | - | Russian | ||
| Ioann | - | Russian | ||
| Iolanthe | ie-ə-LAN-thee (English) | Various |