Phascolarctidae is a family of marsupials of the order Diprotodontia, consisting of only one extant species, the Koala, six well known fossil species, with another 5 less well known fossil species, and 2 fossil species whose taxonomy is debatable but is put in this group. The closest relatives of the Phascolarctidae are the wombats, which comprise the family Vombatidae.
The family of the Phascolarctidae dates back to the Middle Miocene.[2]