| Isma'il | | - | Arabic | |
| Isocrates | | - | Ancient Greek (Latinized) | |
| 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 | |
| Isotta | | ee-ZOT-tah | Italian | |
| 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 | |
| IstvÁN | | - | Hungarian | |
| Itala | | - | Italian | |