| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Killian | - | Irish, French | ||
| Kyran | - | Irish | ||
| LÉAn | - | Irish | ||
| LÍAdÁIn | LEE-din | Irish | ||
| LÍAdan | LEE-din | Irish | ||
| LÍLe | - | Irish | ||
| LÓEgaire | - | Irish Mythology, Ancient Irish | ||
| LÚ | - | Irish Mythology | ||
| LÚCÁS | - | Irish | ||
| LabhrÁS | LOW-raws, LAV-raws | Irish | ||
| Lachtna | - | Irish | ||
| Laoghaire | - | Irish | ||
| Laoise | LEE-sha | Irish | ||
| Leachlainn | - | Irish | ||
| Leary | LEER-ee | Irish |