Marsupials of South America

Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America in the late Cenozoic.

Ameridelphia is traditionally a superorder that includes all marsupials living in the Americas except for the monito del monte (Dromiciops). It is now regarded as a paraphyletic group.

Lutreolina is a genus of opossum found in South America. Both extant species in this genus are known as lutrine opossums. They have an otter-like body plan and occasionally semiaquatic tendencies, hence the genus name Lutreolina, which is Latin for "otter-like".