| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 401 | Garreth | Welsh | Gentle. Modest and brave Sir Gareth was a legendary knight of King Arthur's Round Table. | M | |
| 402 | Garry | Welsh | Diminutive of Gareth: Gentle. Modest and brave Sir Gareth was a legendary knight of King Arthur's Round Table. | M | |
| 403 | Garwyli | Welsh | Legendary son of Gwydaawg Gwyr. | M | |
| 404 | Gary | Welsh | Diminutive of Gareth: Gentle. Modest and brave Sir Gareth was a legendary knight of King Arthur's Round Table. | M | |
| 405 | Gavan | Welsh | Hawk of the battle: white hawk. From the medieval name Gawain. See also Gwayne. | M | |
| 406 | Gavin | Welsh | Hawk of the battle: white hawk. From the medieval name Gawain. See also Gwayne. | M | |
| 407 | Gavyn | Welsh | Hawk of the battle: white hawk. From the medieval name Gawain. See also Gwayne. | M | |
| 408 | Gawain | Welsh | From the Welsh words for little or white hawk. Hawk of the battle. | M | |
| 409 | Geraint | Welsh | A variant of the Latin Gerontius, from the Greek 'geron' meaning old. Famous bearer: Welsh opera singer Sir Geraint Evans. | M | |
| 410 | Gerontius | Welsh | Diminutive of Geraint: A variant of the Latin Gerontius, from the Greek 'geron' meaning old. Famous bearer: Welsh opera singer Sir Geraint Evans. | M | |
| 411 | Gerwyn | Welsh | Fair love. | M | |
| 412 | Gethin | Welsh | Dark-skinned. | M | |
| 413 | Gilbert | Welsh | Legendary son of Cadgyffro. | M | |
| 414 | Gilvaethwy | Welsh | Legendary son of Don. | M | |
| 415 | GIyn | Welsh | Dwells in the glen. | M | |
| 416 | GIynn | Welsh | Dwells in the glen. | M | |
| 417 | Glad | Welsh | Diminutive of Gladys: Derived from the old Welsh name Gwladys, a variant of Claudia, meaning lame. Also derived from the Welsh 'gwledig', meaning territorial ruler. | F | |
| 418 | Gladis | Welsh | Variant of Claudia: Lame. | F | |
| 419 | Gladys | Welsh | Derived from the old Welsh name Gwladys, a variant of Claudia, meaning lame. Also derived from the Welsh 'gwledig', meaning territorial ruler. Famous bearer: British actress Dame Gladys Cooper. | F | |
| 420 | Glan | Welsh | From the shore. | F | |