| Isokrates | | - | Ancient Greek | |
| Isolda | | i-ZOL-də (English), i-SOL-də (English) | Arthurian Romance | |
| Isolde | | i-ZOL-də (English), i-SOL-də (English), ee-ZAWL-du (German) | English (Rare), German, Arthurian Romance | |
| Isra | | - | Arabic | |
| Israa | | - | Arabic | |
| Israel | | IZ-ray-əl (English), IZ-ree-əl (English) | Jewish, English, Biblical, Biblical Greek | |
| Israfil | | - | Judeo-Christian Legend | |
| Israhel | | - | Biblical Latin | |
| Issa | | - | Arabic | |
| Issachar | | IS-ə-kahr (English) | Biblical | |
| Itamar | | - | Hebrew, Biblical Hebrew | |
| Ithai | | i-THAY-ie (English) | Biblical | |
| Ithamar | | - | Biblical, Biblical Latin, Biblical Greek | |
| Ithiel | | - | Biblical | |
| I'tidal | | - | Arabic | |