| Name | Meaning | Gender | Origin |
|---|
| Issac | laughter | Male | Hebrew |
| Jack | after the Georgetown University mascot, Jack the Bulldog | Male | English |
| Jack | From John - God's gracious gift | Male | English |
| Jacob | The supplanter, held by the heel | Male | Hebrew |
| James | From Jacob - To fill the place of another, supplanter. | Male | English |
| James Bond | | Unisex | Hebrew |
| Jazz | The romantic music
| Male | Word |
| Jeeves | | Male | Hebrew |
| Jeff | pledge of peace | Male | English |
| Jellicle | | Unisex | Hebrew |
| Jess | Gift | Male | English |
| Jesse James | | Unisex | Hebrew |
| Jester | A fool at medieval courts | Unisex | |
| Jet | A deep black colour. Aircraft engine that propels an aircraft forward by expelling exhaust gases toward the rear. | Male | Mineral |
| Joker | | Male | Hebrew |
| Junior | Youthful person. Used to distinguish son from father where they have the same name | Male | Latin |
| Junior Mint | | Unisex | Hebrew |
| Jynx | Charm, Spell | Unisex | Latin |
| Keyboard | | Unisex | |
| Klondike | | Male | Hebrew |
| Korky | | Unisex | |
| Maestro | | Male | |
| Magic | Possessing qualities that produce baffling effects | Male | Word |
| Magic | Possessing qualities that produce baffling effects | Male | Word |
| Magpie | | Unisex | |