Melville Island is a vast, uninhabited member of the Canadian arctic islands, Canada with an area of 37,680 km². It is shared by the Northwest Territories, which is responsible for the western half of the island, and Nunavut, which is responsible for the eastern half. The mountains on Melville Island, some of the largest in the western Canadian arctic, reach heights of one kilometre.

The island has little or no vegetation. Where continuous vegetation occurs, it usually consists of hummocks of mosses, lichens, grasses and sedges. The only woody species, the dwarf willow , grows as a dense twisted mat crawling along the ground. However a diverse animal population exists: polar bear, Peary caribou, muskox, collared lemming, arctic wolf, arctic fox, arctic hare and ermine are common. A 2003 sighting of a grizzly bear and grizzly tracks by an expedition from the University of Alberta represents the most northerly report of grizzly bears ever recorded.

Melville Island was first visited by the British explorer Sir William Parry in 1819. Not only did he discover the island, but he was forced to winter over on the inhospitable land until August 1, 1820 due to freeze-up of the sea. The site was named Winter Harbour.

Melville has surfaced as a candidate for natural gas deposits. The first Canadian arctic island exploratory well was spudded in 1961 at Winter Harbour. It drilled Lower Paleozoic strata to a total depth of 3,823 meters. In the 1970s, the northern portion of the island along the Sabine Peninsula proved to contain a major gas field.