| Name | Meaning | Gender | Origin |
|---|
| Jasper | Black stone
| Male | Persian |
| Java | Brewed coffee | Female | Anglicization |
| Jaws | Bones that form the mouth. A dangerous situation - "The Jaws of Death" | Unisex | |
| Jax | God has been gracious: has shown favor. Based on John or Jacques.
| Male | Modern |
| Jekyll | | Unisex | Hebrew |
| Jet | A deep black colour. Aircraft engine that propels an aircraft forward by expelling exhaust gases toward the rear. | Male | Mineral |
| Jett | Jet Black Gem | Male | English |
| Jetta | jet | Female | English |
| Jezebel | follower of idols | Female | Hebrew |
| Jillian | Jove's child. Variant of Gillian from the masculine Julian.
| Female | Phonetic |
| Jinx | Charm, Spell | Female | Latin |
| Job | The Persecuted | Male | Hebrew |
| John | God is merciful | Male | Hebrew |
| Jolly | Full of good humor and high spirits. | Unisex | |
| Josette | Jehovah increases | Female | |
| Jynx | Charm, Spell | Unisex | Latin |
| Kai | Fire
| Male | Hawaiian |
| Kali | after the Indian goddess of death | Female | Sanskrit |
| Kane | tribute, warrior; the doubly-accomplished, golden; man, the eastern sky; beautiful | Male | Celtic |
| Karen | pure | Female | Danish |
| Kat | pure | Female | English |
| Katarina | pure | Female | Czech |
| Keenan | Ancient
| Male | Irish |
| Ken | Male Barbie Doll. | Male | English |
| Killer | | Unisex | |