There are five species of tiny marsupials in this family. They are mouse-sized and are found in Australia and New Guinea.

Pygmy possums have small, triangular heads; long, prehensile tails; and big, round eyes. They are nocturnal, live in trees, and eat insects.

Species in this family include the mountain pygmy possum, the long-tailed pygmy possum, the western pygmy possum, the eastern pygmy possum, and the little pygmy possum.