| Januarius | | - | Ancient Roman | |
| Janus | | - | Roman Mythology | |
| Japheth | | JAY-fəth (English) | Biblical | |
| Japik | | - | Frisian (Rare) | |
| Jaquan | | - | African American (Modern) | |
| Jaqueline | | JAK-ə-leen (English), JAK-ə-lin (English) | English (Modern), Portuguese (Brazilian) | |
| Jaquelyn | | JAK-ə-lin | English (Rare) | |
| Jarah | | - | Biblical | |
| Jared | | JER-əd (English), JAR-əd (English) | English, Biblical | |
| Jareth | | JER-əth (English), JAR-əth (English) | Popular Culture | |
| Jarl | | YAHRL (Norwegian, Swedish, Danish) | Norwegian, Swedish, Danish, Norse Mythology, Ancient Scandinavian | |
| Jarle | | - | Norwegian | |
| Jarmila | | - | Czech, Slovak | |
| Jarogniew | | yah-RAWG-nyef | Polish (Rare) | |
| Jaroslav | | - | Czech, Slovak | |