Polydolopimorphia is an extinct order of metatherians, closely related to extant marsupials.

Known from the Paleocene-Pliocene of South America and the Eocene of Antarctica, they were a diverse group during the Paleogene, filling many niches, before declining and becoming extinct at the end of the Neogene.

[1] It is divided into two suborders, Bonapartheriiformes, and Polydolopiformes[2] Most members are only known from jaw fragments, which have their characteristically generally bunodont teeth.

[3] The morphology of their teeth has led to proposals that polydolopimorphians may be crown group marsupials, nested within Australidelphia,[4] though this proposal, has been questioned, with other analyses finding them outside of crown-group Marsupialia.

[3] The monophyly of the group has been questioned, due to the possibility of the characteristic bunodont teeth emerging convergently in unrelated groups, rather than reflecting a true phylogenetic relationship.