| Isa (3) | | - | Frisian, Ancient Germanic | |
| Isaak | | ee-SAH-ahk (Russian) | Russian, German, Biblical Greek | |
| Isabel | | ee-sah-BEL (Spanish), IZ-ə-bel (English), ee-za-BEL (French), ee-zah-BEL (German) | Spanish, Portuguese, English, French, German | |
| Isabell | | ee-zah-BEL | German | |
| Isabella | | ee-zah-BEL-lah (Italian), iz-ə-BEL-ə (English) | Italian, German, English, Swedish, Norwegian, Danish, Dutch, Romanian | |
| Isabelle | | ee-za-BEL (French), IZ-ə-bel (English), ee-sah-BEL-lə (Dutch) | French, English, German, Dutch | |
| Isbrand | | - | Ancient Germanic | |
| Ishild | | - | Ancient Germanic (Hypothetical) | |
| Isidor | | EE-see-dawr (German) | German, Russian, Macedonian | |
| Isolde | | i-ZOL-də (English), i-SOL-də (English), ee-ZAWL-du (German) | English (Rare), German, Arthurian Romance | |
| Ivo (1) | | EE-vo (German, Dutch, Italian), EE-fo (German), EE-voo (Portuguese) | German, Dutch, Italian, Portuguese, Czech, Ancient Germanic | |
| Ivonne | | ee-VAWN (German) | Spanish, German, Dutch | |