| Name | Meaning | Gender | Origin |
|---|
| Julius | after Julius Caesar | Male | Latin |
| June | 6Th Month | Female | English |
| Juno | queen of the heavens | Female | Latin |
| Justa | Just, Fairness | Unisex | Latin |
| Justice | Just, Fairness | Female | English |
| Justin | just, true | Male | Latin |
| Justine | just, true | Female | |
| Justus | Just | Male | Roman |
| Kahlil | after Lebanese writer Kahlil Gibran | Male | Arabic |
| Kai | Fire
| Male | Hawaiian |
| Kalika | rosebud | Unisex | |
| Kalila | beloved | Female | Arabic |
| Kalyn | Slender | Unisex | English |
| Kamala | lotus | Female | Hindi |
| Kane | tribute, warrior; the doubly-accomplished, golden; man, the eastern sky; beautiful | Male | Celtic |
| Karen | pure | Female | Danish |
| Kasha | | Unisex | Hebrew |
| Katelyn | pure | Female | Spelling |
| Katherine | Pure. Used since third century A.D. Early Latin forms Katerina and Caterina became Katharine and Catherine. French Cateline and English Catlyn came into wider use during medieval period when variants multiplied.
| Female | Greek |
| Kathleen | Innocent
| Female | Anglicized |
| Kattie | pure | Female | Short |
| Katy | pure | Female | Short |
| Katy | pure | Female | Short |
| Kaycee | Vigilant, Watchful | Unisex | English |
| Keegan | A thinker: fiery. Form of Hugh.
| Male | Irish |