| Streptogyna P. Beauv., 1812 |
| Streptogyna americana C.E. Hubb., 1956 |
| Streptogyneae C.E. Calderón & Soderstr., 1980 |
| Strombodurus Steud., 1841 |
| Stylagrostis Mez, 1922 |
| Stylagrostis (Mez) Rúgolo & X. Villavicencio, 1995 |
| Suardia Schrank, 1820 |
| Swallenochloa McClure, 1973 |
| Syllepis E. Fourn., 1886 |
| Syllepis polystachya (Sw.) E. Fourn. ex Hack., 1883 |
| Syllepis ruprechtii E. Fourn., 1886 |
| Symbasiandra Steud., 1840 |
| Synaphe Dulac, 1867 |
| Synaphe rigida (L.) Dulac, 1867 |
| Syntherisma Walter, 1788 |
| Syntherisma argillacea Hitchc. & Chase, 1917 |
| Syntherisma argyrostachya (Steud.) Hitchc. & Chase, 1917 |
| Syntherisma badia (Scribn. & Merr.) Chase, 1906 |
| Syntherisma bakeri Nash, 1898 |
| Syntherisma barbata (Willd.) Nash, 1898 |