| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Tighearnach | TEER-nakh | Irish | ||
| Toal | - | Irish | ||
| ToirÉAsa | - | Irish | ||
| Toirdhealbhach | - | Irish | ||
| TomÁS | to-MAHS (Spanish), too-MASH (Portuguese) | Spanish, Portuguese, Irish | ||
| Torin | - | Irish | ||
| Treasa | TRA-sa | Irish | ||
| Treasach | - | Irish | ||
| Tuathal | - | Irish (Rare) | ||
| Turlough | - | Irish |