| Isingoma | | - | Eastern African, Ganda | |
| Isis | | IE-sis (English) | Egyptian Mythology (Hellenized) | |
| Iskandar | | - | Arabic, Indonesian, Malay | |
| Iskra | | - | Bulgarian, Macedonian, Croatian, Serbian | |
| Ismael | | - | Spanish, Biblical Greek | |
| 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 | |
| Israfil | | - | Judeo-Christian Legend | |
| IstvÁN | | - | Hungarian | |
| Itala | | - | Italian | |
| Italia | | - | Italian | |
| Italo | | - | Italian | |