| Name | Meaning | Gender | Origin |
|---|
| Jazz | The romantic music
| Male | Word |
| Jelly | | Unisex | Hebrew |
| Jet | A deep black colour. Aircraft engine that propels an aircraft forward by expelling exhaust gases toward the rear. | Male | Mineral |
| Jet Black | | Unisex | |
| Jimmy | supplanter | Male | English |
| Job | The Persecuted | Male | Hebrew |
| John | God is merciful | Male | Hebrew |
| Jones | God Will Bring | Male | Welsh |
| Jose | Jehovah increases | Male | Spanish |
| Jovi | after Jon Bon Jovi | Unisex | |
| Juice | | Unisex | Hebrew |
| Jules | youthful; soft, downy | Male | |
| Jumper | | Male | Hebrew |
| Junior | Youthful person. Used to distinguish son from father where they have the same name | Male | Latin |
| Kai | Fire
| Male | Hawaiian |
| Kaiser | Any of the emperors of The Holy Roman Empire, Austria or Germany | Unisex | |
| Kandy | Cutie
| Male | |
| Kane | tribute, warrior; the doubly-accomplished, golden; man, the eastern sky; beautiful | Male | Celtic |
| Killian | church | Male | Irish |
| Kit Kat | | Unisex | |
| Kit Kat | | Unisex | |
| Klaus | Scandinavian and German variation of Nicolas | Male | |
| Klondike | | Male | Hebrew |
| Koda | | Male | |
| Lace | From Lassy, Normandy | Unisex | English |