| Ixaka | Laughs | Male |
| Izar | Star | Female |
| Izarra | Star | Female |
| Izazkun | Reference To The Virgin Mary | Female |
| Jacobe | Supplanter | Male |
| Jaione | Reference To The Nativity | Female |
| Jakinda | Hyacinth | Female |
| Jakome | Basque Form Of James (Supplanter) | Male |
| Jasone | Assumption | Female |
| Javier | Bright. Variant Of Xavier. | Male |
| Jokin | God Will Establish | Male |
| Jokine | God Shall Establish | Female |
| Jone | Gift From God | Female |
| Joseba | God Will Multiply | Male |
| Joska | Hungarian Form Of Joseph (God Is Gracious) | Male |
| Josu | God Saves | Male |
| Josune | Named For Jesus | Female |
| Joxepa | God Will Add | Female |
| Kasen | Pure | Male |
| Kemen | Strong | Male |
| Kepa | Stone | Female |
| Kerbasi | Warrior | Male |
| Kerman | German | Male |
| Kermeilde | Gilded | Female |
| Kontxesi | Refers To The Immaculate Conception | Female |