| Ochoterenella caballeroi Esslinger, 1987 |
| Ochoterenella chiapensis Esslinger, 1988 |
| Ochoterenella digiticauda Caballero, 1944 |
| Ochoterenella figueroai Esslinger, 1988 |
| Ochoterenella lamothei Esslinger, 1988 |
| Ochoterenella nanolarvata Esslinger, 1987 |
| Onchocerca Diesing, 1841 |
| Onchocerca gutturosa Neumann, 1910 |
| Onchocerca lienalis (Stiles, 1892) Railliet & Henry, 1910 |
| Onchocercidae Leiper, 1911 |
| Onchocercinae Leiper, 1911 |
| Oswaldofilaria Travassos, 1933 |
| Oswaldofilaria brevicaudata (Rodhain & Vuylsteke, 1937) |
| Oswaldofilariinae Chabaud & Choquet, 1953 |
| Parachandlerella Caballero, 1948 |
| Parachandlerella periarterialis Caballero, 1948 |
| Pelecitus Railliet & Henry, 1910 |
| Pelecitus meridionaleporinus Jiménez-Ruiz, Gardner, Cervantes & Lorenzo, 2004 |
| Piratuba Freitas & Lent, 1947 |
| Piratuba lanceolata Peláez & Pérez-Reyes, 1960 |