| Oedicephalus cephalotes (Cresson, 1874) |
| Oedicephalus frater Townes, 1946 |
| Oedicephalus glucidatus Cameron, 1885 |
| Oedicephalus gracilicornis Cresson, 1868 |
| Oedicephalus longicornis Cresson, 1868 |
| Oedicephalus sororius Cresson, 1868 |
| Oedicephalus vicinus (Cresson, 1874) |
| Olesicampa Thomson, 1887 |
| Olesicampe Förster, 1869 |
| Olesicampe albispina (Cameron, 1886) |
| Olesicampe alpestris (Cameron, 1886) |
| Olesicampe montezuma (Cameron, 1886) |
| Oleter Shestakov, 1926 |
| Oligoplectron Förster, 1868 |
| Omoborus Förster, 1869 |
| Omorgus Förster, 1868 |
| Oncocotta Dasch, 1974 |
| Ophiomorpha Szépligeti, 1905 |
| Ophion Fabricius, 1798 |
| Ophion (Dispilus) Szépligeti, 1906 |