| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 401 | Germaine | Celtic | Loud of voice. | F | |
| 402 | Gervase | Celtic | Servant spear. This name is derived from combining an Old Gcrman name meaning spear, and the Celtic word for servant. Famous bearer: martyr St Gervase who died in Milan. | M | |
| 403 | Gilda | Celtic | Serves God. | F | |
| 404 | Gildas | Celtic | Serves God. | F | |
| 405 | Gildas | Celtic | Serves God. | M | |
| 406 | Gilmore | Celtic | Serves Mary. | M | |
| 407 | Gilroy | Celtic | Serves the red haired lord. | M | |
| 408 | Ginebra | Celtic | White as foam. | F | |
| 409 | Ginerva | Celtic | White as foam. | F | |
| 410 | Ginessa | Celtic | White as foam. | F | |
| 411 | Gitta | Celtic | Strong. | F | |
| 412 | Glen | Celtic | From the valley. | M | |
| 413 | Glenn | Celtic | From the valley. | M | |
| 414 | Glifieu | Celtic | Mythical son of Taran. | M | |
| 415 | Glyn | Celtic | From the valley. | M | |
| 416 | Gorsedd | Celtic | From Arbeth. | M | |
| 417 | Grania | Celtic | Love. | F | |
| 418 | Gruddieu | Celtic | Mythical son of Muriuel. | M | |
| 419 | Guenevere | Celtic | White lady. | F | |
| 420 | Guennola | Celtic | White. | F | |