| Name | Meaning | Gender | Origin |
|---|
| Irwin | boar friend | Male | English |
| Iverson | | Unisex | Hebrew |
| Ivor | yew | Male | Scottish |
| Jacobson | | Unisex | Hebrew |
| Jameson | son of James | Male | English |
| Jansen | Variant Of The Hebrew John Jehovah Has Been Gracious; Has Shown Favor. | Unisex | German |
| Janssen | | Unisex | Hebrew |
| Jarvis | driver, a conqueror | Male | English |
| Jason | the Lord is salvation | Male | Hebrew |
| Jerold | Variant of Gerald Rules by the spear.
| Male | |
| Jerry | after Jerry Garcia, The Grateful Dead | Male | English |
| 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 |
| Jock | God has been gracious: has shown favor. Based on John or Jacques.
| Male | Scottish |
| Johnson | Son of John
| Male | English |
| Johnston | From John's farm
| Male | |
| Juliet | youthful | Female | English |
| Justice | Just, Fairness | Female | English |
| Kaiden | Fighter | Unisex | American |
| Kane | tribute, warrior; the doubly-accomplished, golden; man, the eastern sky; beautiful | Male | Celtic |
| Kayleigh | Slender | Unisex | English |
| Keith | wood, wind; wood-dweller | Male | Scottish |
| Kelli | From The Wood | Unisex | Welsh |
| Kelly | Lively: aggressive.
| Female | Irish |
| Kimberly | Cyneburga's Royal Forest, Meadow | Female | English |