| Onthophagus nitidior Bates, 1887 |
| Onthophagus nudifrons Balthasar, 1939 |
| Onthophagus nyctopus Bates, 1887 |
| Onthophagus oaxacanus Zunino & Halffter, 1988 |
| Onthophagus omiltemius Bates, 1887 |
| Onthophagus orizabensis Moctezuma, Joaqui & Sánchez-Huerta, 2019 |
| Onthophagus padrinoi Delgado, 1999 |
| Onthophagus parafuscus Zunino & Halffter, 2005 |
| Onthophagus pedester Howden & Génier, 2004 |
| Onthophagus petenensis Howden & Gill, 1993 |
| Onthophagus potosinus Moctezuma & Halffter, 2020 |
| Onthophagus praecellens Bates, 1887 |
| Onthophagus pseudofuscus Zunino & Halffter, 1988 |
| Onthophagus pseudoguatemalensis Moctezuma & Halffter, 2021 |
| Onthophagus pseudoundulans Zunino & Halffter, 1988 |
| Onthophagus pseudoundulans subsp. howdeni Zunino & Halffter, 1988 |
| Onthophagus pseudoundulans subsp. pseudoundulans Zunino & Halffter, 1988 |
| Onthophagus retusus Harold, 1869 |
| Onthophagus reyesi Zunino & Halffter, 1988 |
| Onthophagus rhinolophus Harold, 1869 |