| Nomada Scopoli, 1770 |
| Nomada surinamensis Retzius, 1783 |
| Nomadinae Latreille, 1802 |
| Nomadini Latreille, 1802 |
| Odyneropsis Schrottky, 1902 |
| Odyneropsis apicalis Ducke, 1909 |
| Oreopasites Cockerell, 1906 |
| Oreopasites (Oreopasites) Cockerell, 1906 |
| Oreopasites (Oreopasites) arizonica Linsley, 1941 |
| Oreopasites (Oreopasites) collegarum Rozen, 1992 |
| Oreopasites (Oreopasites) favreauae Rozen, 1992 |
| Osirini Handlirsch, 1925 |
| Osiris Smith, 1854 |
| Osiris fasciatus (Radoszkowski, 1844) |
| Osiris marginatus Cresson, 1878 |
| Osiris mexicanus Cresson, 1878 |
| Osiris opsionomus Shanks, 1987 |
| Osiris semiatratus Shanks, 1988 |
| Oxytrigona Cockerell, 1917 |
| Oxytrigona mediorufa (Cockerell, 1912) |