| Name | Meaning | Gender | Origin |
|---|
| Isaac | laughing one | Male | Hebrew |
| Isabelle | pledged to God | Female | |
| Jacques | supplanter | Male | |
| Jean | God is gracious | Male | |
| Jeanette | French variation of Jean, God is gracious | Female | |
| Josephine | God will increase | Female | |
| Josette | Jehovah increases | Female | |
| Joy | From Joyce - Gay and joyful | Female | Word |
| Joyce | after James Augustine Aloysius Joyce, Irish writer and poet | Female | Latin |
| Jules | youthful; soft, downy | Male | |
| Juliette | youthful | Female | |
| Keiko | Japanese for happy or beloved | Female | Japanese |
| Koji | | Unisex | Hebrew |
| Lacey | Cheerful One | Female | English |
| Lafayette | Hound Dog from the AristoCats
| Male | |
| Lance | knight's attendant; land | Male | English |
| Lara | citadel | Female | Russian |
| Larissa | name of a city, mythical woman; cheerful one | Female | Ltin |
| Launcelot | Knight of Arthur and lover of Guinevere
| Male | |
| Leda | happy | Female | Greek |
| Leon | lion | Male | Greek |
| Leroy | The king.
| Male | |
| Lise | Abbreviation of Elisabeth. My God is bountiful:God of plenty: devoted to God.
| Female | |
| Lorraine | From Lorraine
| Female | |
| Luc | man from Lucania | Male | |