The Southwest National Park is a 618,267-hectare (1,527,770-acre) national park in the south-west of Tasmania, Australia. The park is the largest in Tasmania and is part of the Tasmanian Wilderness World Heritage Area.

The eastern side of the park is 93 kilometres (58 mi) west of Hobart and the park stretches to the west and south coasts. This park covers most of the wilderness areas in Tasmania's south west. The park is well known for its untouched wilderness and remoteness. Weather in the park is can change quickly, and can be severe. The area has not been changed by humans. Evidence shows that Tasmanian Aborigines have visited the area for at least 25,000 years. European settlers have made a few trips into the park, but there has been very few long lasting settlements and little change to the natural environment. Within the area there is only one road, to the hydroelectricity township of Strathgordon. The southern and western parts the park can only be reached by foot, boat, or light aircraft.

The tiny town of Melaleuca in the extreme south-west has a runway for airplanes to land, and basic facilities for the National Parks Service.