Wilsons Promontory, colloquially known as Wilsons Prom or The Prom, is a peninsula that forms the southernmost part of the Australian mainland, located in the state of Victoria.

South Point at 39°08′06″S 146°22′32″E / 39.13500°S 146.37556°E / -39.13500; 146.37556 is the southernmost tip of Wilsons Promontory and hence of mainland Australia. Located at nearby South East Point, (39°07′S 146°25′E / 39.117°S 146.417°E / -39.117; 146.417) is the Wilsons Promontory Lighthouse. Most of the peninsula is protected by the Wilsons Promontory National Park and the Wilsons Promontory Marine National Park.

The promontory was first occupied by indigenous Koori people at least 6,500 years prior to European arrival. Middens along the western coast indicate that the inhabitants subsisted on a seafood diet.

The promontory is mentioned in dreamtime stories, including the Bollum-Baukan, Loo-errn and Tiddalik myths. It is considered the home of the spirit ancestor of the Brataualung clan - Loo-errn. The area remains highly significant to the Gunai/Kurnai and the Boon wurrung people, who consider the promontory to be their traditional country/land.

The first European to see the promontory was George Bass in January 1798. He initially referred to it as "Furneaux's Land" in his diary, believing it to be what Captain Furneaux had previously seen. But on returning to Port Jackson and consulting Matthew Flinders he was convinced that the location was so different it could not be that land.

Seal hunting was conducted in the area in the 19th century. Shore-based whaling was also carried out in a cove at Wilsons Promontory from at least 1837. It was still underway in 1843 at Lady's Bay (Refuge Cove).

Throughout the 1880s and '90s a public campaign to protect the area as a national park was waged, including by the Field Naturalists' Club of Victoria. The promontory has been a national park, to one degree or another, since 1898. Wilsons Promontory National Park, also known locally as "the Prom", contains the largest coastal wilderness area in Victoria. Until the 1930s, when the road was completed, it was accessible only by boat. The site was closed to the public during World War II, as it was used as a commando training ground. The only settlement within Wilsons Promontory is Tidal River which lies 30 kilometres (19 mi) south of the park boundary and is the focus for tourism and recreation. This park is managed by Parks Victoria. In 2005 a burn started by staff got out of control and burnt 13% of the park, causing the evacuation of campers. In 2009, a lightning strike near Sealer's Cove started a fire that burned over 25,000 hectares (62,000 acres). Much of the area had not been burned since 1951. The fire began on 8 February, the day after "Black Saturday", where an intense heat wave, combined with arson, faulty electrical infrastructure and natural causes, led to hundreds of bushfires burning throughout the state of Victoria. Although the fire burned to within 1 kilometre (0.62 mi), the Tidal River camping area and park headquarters were unaffected. The park reopened to the public one month after the incident and the burned areas quickly regrew. Despite the damage, the natural beauty of the area remained largely intact.

In March 2011 a significant rainfall event led to major flooding of the Tidal River camping area. The bridge over Darby River was cut, leaving no vehicle access to Tidal River, leading to the evacuation of all visitors by helicopter over the following days, and the closure of the southern section of the park. In September 2011 public access to Tidal River was reopened following repair of the main access road, and the bridge at Darby River. All sections of the park south of Tidal River were closed while further repairs of tracks and footpaths were undertaken. The park was fully re-opened by Easter of 2012.