| 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 | |
| JÖRdis | | - | German | |
| JÖRg | | YUURK | German | |
| JÜRgen | | YUYR-gen | Low German | |
| Jakob | | YAH-kawp (German), YAH-kob (Danish) | German, Swedish, Norwegian, Danish, Icelandic, Dutch, Slovene | |
| Jan (1) | | YAHN (Dutch, Swedish, Norwegian, Polish, German) | Dutch, Swedish, Norwegian, Danish, Czech, Polish, Slovene, German, Catalan | |
| Jana (1) | | YAH-nah (Dutch, German) | Czech, Slovak, Dutch, German, Slovene, Catalan | |
| Janina | | yah-NEE-nah (Polish, German), YAH-nee-nah (Finnish) | Polish, Finnish, German, Swedish, Lithuanian | |