| Named By: | Ameghino in 1887 |
| Time Period: | Early-Late Miocene (Santacrucian-Huayquerian)~17.5-6.8 Ma |
| Location: | Argentina, Bolivia |
| Size: | 1.2 meters long |
| Diet: | Herbivore |
| Fossil(s): | Few specimens |
| Classification: | | Chordata | Mammalia | Litopterna | Proterotheriidae | |
Diadiaphorus is an extinct genus of litoptern mammal from the Miocene of Argentina (Ituzaingo, Pinturas, Chiquimil and Santa Cruz Formations) and Bolivia (Nazareno Formation), South America.