| Onthophagus guatemalensis Bates, 1887 |
| Onthophagus halffteri Zunino, 1981 |
| Onthophagus hidalgus Zunino & Halffter, 1988 |
| Onthophagus hippopotamus Harold, 1869 |
| Onthophagus hoepfneri Harold, 1869 |
| Onthophagus howdeni Zunino & Halffter, 1988 |
| Onthophagus howdenorum Zunino & Halffter, 1988 |
| Onthophagus igualensis Bates, 1887 |
| Onthophagus incensus Say, 1835 |
| Onthophagus inecolorum Moctezuma & Halffter, 2020 |
| Onthophagus inflaticollis Bates, 1889 |
| Onthophagus iodiellus Bates, 1887 |
| Onthophagus istmenus Moctezuma, Sánchez-Huerta & Halffter, 2020 |
| Onthophagus ixtepecorum Moctezuma & Halffter, 2020 |
| Onthophagus ixtlanensis Moctezuma & Halffter, 2020 |
| Onthophagus jalapensis Balthasar, 1939 |
| Onthophagus jaliscensis Zunino & Halffter, 1988 |
| Onthophagus knausi Brown, 1927 |
| Onthophagus knulli Howden & Cartwright, 1963 |
| Onthophagus landolti Harold, 1880 |