Phalangeriformes /fəˈlændʒərɪfɔːrmiːz/ is a paraphyletic[1] suborder of about 70 species of small to medium-sized arboreal marsupials native to Australia, New Guinea, and Sulawesi.

The common name "(o)possum" for various Phalangeriformes species derives from the creatures' resemblance to the opossums of the Americas (the term comes from Powhatan language aposoum "white animal", from Proto-Algonquian *wa·p-aʔɬemwa "white dog").

The largest are the two species of bear cuscus, which may exceed 7 kg (15 lb 7 oz).

They inhabit most vegetated habitats, and several species have adjusted well to urban settings.

About two-thirds of Australian marsupials belong to the order Diprotodontia, which is split into three suborders, namely the Vombatiformes (wombats and the koala, four species in total); the large and diverse Phalangeriformes (the possums and gliders) and Macropodiformes (kangaroos, potoroos, wallabies and the musky rat-kangaroo).