| Theory | Unisex | Latin Names |
| Théotime | Man | French Names |
| Theotimus | Man | Greek Names |
| Thera | Woman | Greek Names |
| Theresa | Woman | Greek Names |
| Therese | Woman | French Names |
| Theresia | Woman | Greek Names |
| Theria | Woman | Greek Names |
| Therius | Man | Greek Names |
| Theron | Unisex | Greek Names |
| Thessaly | Unisex | Greek Names |
| Theta | Woman | Greek Names |
| Thetis | Woman | Greek Names |
| Theudo | Man | German Names |
| Theunis | Man | Dutch Names |
| Thi | Woman | Vietnamese Names |
| Thiago | Man | Latin Names |
| Thian | Man | Vietnamese Names |
| Thibault | Man | French Names |
| Thierry | Man | French Names |