| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Tegid | - | Welsh | ||
| Tegwen | - | Welsh | ||
| Tesni | - | Welsh | ||
| Tiwlip | - | Welsh | ||
| Tomi | TO-mee (Finnish) | Finnish, Hungarian, Welsh | ||
| Tomos | TAW-maws | Welsh | ||
| Trahaearn | - | Welsh | ||
| Traherne | - | Welsh | ||
| Trefor | - | Welsh | ||
| Trev | TREV (English) | Welsh, English | ||
| Trevor | TRE-vər (English) | Welsh, English | ||
| Tristan | TRIS-tən (English), trees-TAWN (French) | Welsh, English, French, Arthurian Romance | ||
| Trystan | - | Welsh | ||
| Tudor (1) | - | Welsh | ||
| Tudur | - | Welsh |