| Iseut | | - | Medieval English | |
| Isiah | | ie-ZIE-ə | English | |
| Isidora | | ee-see-DHO-rah (Spanish), ee-zee-DO-rah (Italian), iz-i-DAWR-ə (English) | Serbian, Macedonian, Spanish, Portuguese, Russian (Rare), Italian (Rare), English (Rare), Ancient Gr | |
| Isidore | | IZ-i-dawr (English), ee-zee-DOR (French) | English, French, Georgian, Jewish | |
| Isolde | | i-ZOL-də (English), i-SOL-də (English), ee-ZAWL-du (German) | English (Rare), German, Arthurian Romance | |
| Israel | | IZ-ray-əl (English), IZ-ree-əl (English) | Jewish, English, Biblical, Biblical Greek | |
| Issac | | IE-zək | English | |
| Issy | | - | English | |
| Ivonette | | - | English (Rare) | |
| Ivor | | IE-vawr (English), EE-vawr (English) | Irish, Scottish, Welsh, English (British) | |
| Ivy | | IE-vee | English | |
| Izabelle | | IZ-ə-bel | English (Modern) | |
| Izzy | | IZ-ee | English | |