The Pygmy Mouse-lemur (Microcebus myoxinus) is the smallest of the mouse-lemurs and the smallest primate in the world, only weighing around 30 grams (roughly 1 ounce). Its dorsal side is a rufous-brown colour, and creamy-white ventrally. They live in dry deciduous forests.

The Pygmy Mouse-lemur measures around 6.2 cm. Its small size and nocturnal nature made it difficult to locate for over a century, and was rediscovered in the Kirindy forest in western Madagascar in 1993. They are believed to inhabit other parts of the island, but so far have only been discovered in a localised area.

They rest during the day, and have a tendency to sleep in the open, which increases the risk of predation; although this danger is somewhat mitigated by sleeping alone. They can also use the abandoned nests of the Giant Mouse-lemur.