| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| JÁN | - | Slovak | ||
| JÚLia | ZHOO-lyə (Portuguese), YOO-lee-aw (Hungarian) | Portuguese, Catalan, Hungarian, Slovak | ||
| JÚLius | - | Slovak | ||
| Jakub | YAH-kuwp (Polish) | Polish, Czech, Slovak | ||
| Jana (1) | YAH-nah (Dutch, German) | Czech, Slovak, Dutch, German, Slovene, Catalan | ||
| Janka | - | Slovak | ||
| Janko | - | Slovene, Croatian, Serbian, Slovak | ||
| Jarmila | - | Czech, Slovak | ||
| Jaroslav | - | Czech, Slovak | ||
| Jaroslava | - | Czech, Slovak | ||
| Jela | - | Serbian, Croatian, Slovak | ||
| Jolana | - | Czech, Slovak | ||
| JonÁŠ | - | Czech, Slovak | ||
| Jozef | YO-zəf (Dutch) | Slovak, Dutch | ||
| JozefÍNa | - | Slovak |