| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Iacomus | - | Late Roman | ||
| Ieronimus | - | Late Roman | ||
| Ignatia | - | Late Roman | ||
| Ignatius | ig-NAY-shəs (English) | Late Roman | ||
| Innocentius | - | Late Roman | ||
| Iosephus | - | Late Roman | ||
| Isaura | ee-SOW-rah (Spanish) | Portuguese, Spanish, Late Roman | ||
| Isaurus | - | Late Roman | ||
| Isidorus | - | Late Roman | ||
| Iucunda | - | Late Roman | ||
| Iustina | - | Late Roman | ||
| Iustinianus | - | Late Roman | ||
| Iustinus | - | Late Roman | ||
| Iustus | - | Late Roman |