 | Finola | Fair Shouldered |  |
 | Fionan | Fair | |
| Fionn | Fair-haired | |
| Fionnuala | Fair shouldered | |
| Fionnula | Fair shoulder | |
| Fitzgerald | Son of Gerald | |
| Flann | Red | |
| Flannerry | Descendant of the red warrior | |
| Flannery | Descendant of the red warrior | |
| Gallagher | Eager helper | |
| Galvin | Sparrow | |
| Gannon | Fair skinned | |
| Garrett | Brave warrior | |
| Gilmore | Servant of Mary | |
| Gilroy | Servant of the redhead | |
| Giolla | Servant | |
| Glen | Glen; valley | |
| Glenna | Valley; glen | |
| Grady | Descendant of the noble one | |
| Grian | Sun | |
| Herne | Descendant of the horse lord | |
| Hogan | Descendant of the young warrior | |
| Kaitlin | Pure | |
| Kaitlyn | Pure | |
| Kane | Battle | |
| Kathan | Battle victor | |
| Kathleen | Pure | |
