| Name | Meaning | Gender | Origin |
|---|
| Jasper | Black stone
| Male | Persian |
| Jasper | Black stone
| Male | Persian |
| Jasper | Black stone
| Male | Persian |
| Jeeves | | Male | Hebrew |
| Jefferson | son of Jeffrey | Male | English |
| Jeffrey | pledge of peace | Male | Spelling |
| Jen | White, Fair | Unisex | English |
| Jerry | after Jerry Garcia, The Grateful Dead | Male | English |
| Jilly | Downy Haired | Unisex | English |
| Jimmy | supplanter | Male | English |
| Jip | | Male | |
| Jodie | From Judith - Admired and praised | Unisex | |
| Johnn | Variant of the Hebrew John Jehovah has been gracious: has shown favor.
| Male | |
| Johnson | Son of John
| Male | English |
| Johnston | From John's farm
| Male | |
| Joker | | Male | Hebrew |
| Joli | Cheerful; Pretty. | Unisex | English |
| Jon | God is gracious; or gift of Jehovah | Male | English |
| Jonas | Dove. Variant of Hebrew Jonah.
| Male | Greek |
| Jr. | | Unisex | Hebrew |
| Justin | just, true | Male | Latin |
| K.C. | Kitchen Cat | Unisex | |
| Kacee | Cathasaigh's Heir | Unisex | English |
| Kaci | Cathasaigh's Heir | Unisex | English |
| Kadi | Rhyming Variant Of Katy Or Cady. | Unisex | English |