| Name | Meaning | Gender | Origin |
|---|
| Jill | Down-bearded youth | Female | Latin |
| Jim | Supplanter | Male | Hebrew |
| Jinn | | Unisex | Hebrew |
| Jinx | Magic charm | Female | Latin |
| Jo | He will enlarge | Unisex | Hebrew |
| Joan | God is gracious | Female | Hebrew |
| Job | Hated | Male | Hebrew |
| Jock | Supplanter | Male | English |
| Joe | He will enlarge | Male | Hebrew |
| Jove | Zeus, Father | Male | Roman |
| Joy | Joy | Female | English |
| Joyce | Experienced in battle | Female | Breton |
| Judd | Descend | Male | Hebrew |
| Jude | Praise | Male | Hebrew |
| Jules | Down-bearded youth | Unisex | Latin |
| June | The sixth month of the year | Female | English |
| Kai | Rejoice | Male | Finnish |
| Kale | Uncertain, perhaps slender | Male | Gaelic |
| Kane | A spear | Female | Hebrew |
| Karl | Free man | Male | Germanic |
| Kate | Pure | Female | Greek |
| Kay | Pure | Male | Greek |
| Keane | Descendant of Cathán | Male | Gaelic |
| Keefe | Handsome | Male | English |
| Keene | Ancient. | Male | English |
| Keith | Woods | Male | Gaelic |
| Kell | Farm By The Spring | Male | English |
| Kemp | Battler, fighter, warrior | Male | English |
| Ken | Born of fire | Male | Gaelic |
| Kent | Uncertain, perhaps coastal region | Male | English |