| Named By: | Richard Owen in 1872 |
| Time Period: | Unavailable |
| Location: | Australia, South Australia, Lake Callabonna |
| Size: | Largest species estimated about 200 kg in weight |
| Diet: | Herbivore |
| Fossil(s): | Skulls and partial post cranial remains |
| Classification: | | Chordata | Mammalia | Marsupialia | Diprotodontia | Vombatidae | |
| Also known as: | | Phascolomys gigas | |
Phascolonus was a genus of prehistoric Australian marsupials in the wombat family. The largest species, Phascolonus gigas, weighed as much as 200 kg (450 lb). Phascolonus existed alongside an even larger marsupial, Diprotodon, which weighed as much as three tons and was distantly related to wombats. Both disappeared at the end of the Late Pleistocene in a Quaternary extinction event together with many other large Australian animals.
At Tea Tree Cave, a two-million-year-old Phascolonus fossil was found alongside that of the crocodilian Quinkana.