| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Isocrates | - | Ancient Greek (Latinized) | ||
| Isokrates | - | Ancient Greek | ||
| Iudicael | - | Ancient Celtic | ||
| Iudocus | - | Ancient Celtic (Latinized) | ||
| Iulia | YOO:-li-a (Ancient Roman) | Romanian, Ancient Roman | ||
| Iuliana | - | Romanian, Ancient Roman | ||
| Iulianus | - | Ancient Roman | ||
| Iulius | YOO:-li-uws | Ancient Roman | ||
| Iunia | - | Ancient Roman, Biblical Latin | ||
| Iunius | - | Ancient Roman | ||
| Iuvenalis | - | Ancient Roman | ||
| Ivo (1) | EE-vo (German, Dutch, Italian), EE-fo (German), EE-voo (Portuguese) | German, Dutch, Italian, Portuguese, Czech, Ancient Germanic |