| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 601 | Tawni | Irish | A green field; the warm sandy color of a lion's coat. | F | |
| 602 | Tawnia | Irish | A green field; the warm sandy color of a lion's coat. | F | |
| 603 | Tawnie | Irish | A green field; the warm sandy color of a lion's coat. | F | |
| 604 | Tawny | Irish | A green field; the warm sandy color of a lion's coat. | F | |
| 605 | Tawnya | Irish | A green field; the warm sandy color of a lion's coat. | F | |
| 606 | Teagan | Irish | Good-looking. | F | |
| 607 | Teamhair | Irish | Where the kings met. | F | |
| 608 | Tegan | Irish | Good-looking. | F | |
| 609 | Teige | Irish | Good-looking. | F | |
| 610 | Tipper | Irish | Nickname and variant of the Irish name Tabar meaning a well. | F | |
| 611 | Toireasa | Irish | Strong. | F | |
| 612 | Treasa | Irish | Strong. | F | |
| 613 | Treise | Irish | Strong. | F | |
| 614 | Tullia | Irish | Peaceful. | F | |
| 615 | Ulicia | Irish | Feminine form of Ulik. | F | |
| 616 | Una | Irish | Lamb; together. | F | |
| 617 | Unity | Irish | Together. | F | |
| 618 | Uny | Irish | Together. | F | |
| 619 | Vevila | Irish | Harmony. | F | |
| 620 | Vevina | Irish | Sweet lady. | F | |