| Kiona | Variant of Kian. Ancient. |
| Kionah | Variant of Kian. Ancient. |
| Kioni | Variant of Kian. Ancient. |
| Kionna | Variant of Kian. Ancient. |
| Kollin | of the name collin, virile |
| Konnyr | Strong willed or Wise Hound-Lover. Variant of Connor. |
| Kyanna | A name meaning divine or heavenly. |
| Kye | A place-name referring to the narrows: a wood or a church. |
| Kylan | A place-name referring to the narrows: a wood or a church. |
| Kylar | A place-name referring to the narrows: a wood or a church. |
| Kyle | A place-name referring to the narrows: a wood or a church. |
| Kylen | A place-name referring to the narrows: a wood or a church. |
| Kyler | A place-name referring to the narrows: a wood or a church. |
| Kyran | Beam of Light.; Dusky; dark-haired.; Lord Sir; Variant of Kieran, Dark or Black |
| Kyrell | A place-name referring to the narrows: a wood or a church. |
| Labhaoise | A name meaning warrior. |
| Laetitia | Irish form of Letitia happy |
| Lakeland | Home of the Norse |
| Lalor | Derived from a Gaelic name. |
| Lany | A diminutive of the name Lana |
| Laoghaire | Derived from the Gaelic for calf herder. |
| Laoidhigh | An Irish name meaning a poetic song. |
| Laoise | Named after a legendary Irish princess. |
| Laughlin | One who comes from the land of lakes. |
| Leachlainn | Servant of the church. |
| Leary | A descendant of the calf herder. |
| Leathlobhair | A name meaning halfleper man. |
| Leena | Devoted; A devoted one/ tender; Illumination; Variant of Lina: Tender.; Wet meadow. |
| Leila | Born at night.; Dark Beauty; Dark. Born at night. Heroine of Byrons The Giaour (1813).; Dark as night; Night, dark beauty; Nocturnal; Name of a saint; Variant of Layla: Night. Born at night. Sweetheart. |
| Lennon | A small cloak or mantle. |
| Leslie | Dwells at the gray fortress; From the gray fortress; Garden of Hollies; From the holly garden; of the gray fortress; From Leslie; Meadowlands |
| Levane | A name meaning the white moon. |
| Liadan | A name meaning a grey lady poet. |
| Liam | Form of William. |
| Lil | Name of a saint |
| Lochan | Bright eyes; Eye; Eye; eyes; The eyes / one who is lively; Yes |
| Lochlain | Home of the Norse |
| Lochlann | Home of the Norse |
| Loman | One who is a man of the people. |
| Lorcan | Little fierce one. |