| Name | Meaning | Gender | Origin |
|---|
| Ghost | A haunting spirit or memory. One who moves noiselessly. | Unisex | |
| Grant | Bestow or great: tall. The American General and president Ulysses S. Grant. Surname.
| Male | Scottish |
| Grimalkin | | Unisex | Hebrew |
| Guinness | Brand of stout beer from Ireland. | Unisex | |
| Hades | World of the dead or hell. | Male | |
| Hannibal | grace of Baal, god of fertility and fortune | Male | Punic |
| Hecate | Mythical Witchcraft Goddess | Unisex | Greek |
| Hercules | glory of Hera | Male | Greek |
| Hershey | Brand of chocolate. | Male | |
| Hitchcock | | Unisex | Hebrew |
| Hocus | | Male | |
| Hocus Pocus | | Unisex | Hebrew |
| Humberto | Big: bright.
| Male | |
| Ice | Water frozen solid | Unisex | |
| Icicle | | Unisex | Hebrew |
| Ink | | Unisex | |
| Ink Spot | | Unisex | Hebrew |
| Inky | | Unisex | Hebrew |
| Jabbar | powerful, mighty | Male | Arabic |
| Jackal | | Unisex | Hebrew |
| Jaguar | Large Spotted Feline | Male | English |
| Jet | A deep black colour. Aircraft engine that propels an aircraft forward by expelling exhaust gases toward the rear. | Male | Mineral |
| Jethro | excellence | Male | Hebrew |
| Jett | Jet Black Gem | Male | English |
| Jupiter | Zeus, Father | Male | Roman |