| Tess | | TES | English, Dutch | |
| Tessa | | TES-ə | English | |
| Tessie | | TES-ee | English | |
| Tetty | | TET-ee | English (Archaic) | |
| Tex | | TEKS | English | |
| Thad | | THAD | English | |
| Thaddeus | | THAD-ee-əs (English) | English, Biblical, Biblical Latin | |
| Thane | | THAYN | English (Rare) | |
| Thankful | | THANGK-fəl | English (Archaic) | |
| Thea | | TE-ah (German), THEE-ə (English) | German, Swedish, Danish, Norwegian, English | |
| Thelma | | THEL-mə | English | |
| Theo | | THEE-o (English), TAY-o (Dutch) | English, Dutch | |
| Theobald | | THEE-ə-bawld (English) | English (Rare), Ancient Germanic | |
| Theodora | | thee-ə-DAWR-ə (English) | English, Greek, Ancient Greek | |
| Theodore | | THEE-ə-dawr | English | |