The Australian Swamp Rat (Rattus lutreolus) is a mammal in the Muridae family of rodents and true mice. It is also known as the Eastern Swamp Rat.

The Australian Swamp Rat has a stocky body with black-brown fur and black feet. Its underbelly is lighter. It has small, rounded ears, and small, dark, round eyes. It has long, white whiskers. Its tail is long, dark-grey, scaly, and without hair.