| Name | Meaning | Gender | Origin |
|---|
| Ichabod | Glory has Departed | Male | Hebrew |
| Igor | Scottish variation of Welsh Ifor, lord or English form of Scandinavian Ifar, yew | Male | Russian |
| Irina | peace | Female | Russian |
| Iris | rainbow, a play of colours | Female | |
| IT | | Unisex | Hebrew |
| Jack | after the Georgetown University mascot, Jack the Bulldog | Male | English |
| Jack | From John - God's gracious gift | Male | English |
| Jager | Carter | Unisex | English |
| Jaguar | Large Spotted Feline | Male | English |
| Jason | the Lord is salvation | Male | Hebrew |
| Jasper | Black stone
| Male | Persian |
| Jasper | Black stone
| Male | Persian |
| Jasper | Black stone
| Male | Persian |
| Jaws | Bones that form the mouth. A dangerous situation - "The Jaws of Death" | Unisex | |
| Jigsaw | | Unisex | Hebrew |
| Judd | praised | Male | Medieval |
| Katrina | Greek, pure | Female | |
| Lafayette | Hound Dog from the AristoCats
| Male | |
| Lestat | | Unisex | Hebrew |
| Lilly | Lily | Female | English |
| Lucifer | light-bearer | Male | Latin |
| Lucifer | light-bearer | Male | Latin |
| Lugosi | after 1940s Dracula actor Bela Lugosi | Unisex | |
| Lurch | To stagger. | Unisex | |
| Marcus | warlike | Male | Latin |