| Tetrapogon chlorideus (J. Presl) P.M. Peterson, 2015 |
| Thalysia Kuntze, 1891 |
| Thellungia Stapf, 1920 |
| Themeda Forssk., 1775 |
| Themeda foliosa (Kunth) Balansa, 1890 |
| Themeda quadrivalvis (L.) Kuntze, 1891 |
| Thinopyrum Á. Löve, 1980 |
| Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, 1985 |
| Thinopyrum pycnanthum (Godr.) Barkworth, 1998 |
| Thrasya Kunth, 1815 |
| Thrasya (Kunth) Benth. & Hook. f., 1883 |
| Thrasya campylostachya (Hack.) Chase, 1911 |
| Thrasya ciliatifolia Swallen, 1943 |
| Thrasya gracilis Swallen, 1943 |
| Thrasya petrosa (Trin.) Chase, 1911 |
| Thrasya villosa Hitchc., 1927 |
| Thurberia Benth., 1881 |
| Thyridostachyum Nees, 1836 |
| Thysanachne C. Presl, 1829 |
| Thysanachne peruviana J. Presl, 1830 |