Wadbilliga National Park, Nature reserve in New South Wales, Australia.

Wadbilliga National Park covers 985.3 km² of high country spanning the Monaro and South Coast regions of south-eastern New South Wales. Its undulating plateaus and steep gullies fall from a maximum elevation of 1,335 m to a minimum of 15 m. Pinkwood rainforest grows in sheltered, fire-free gullies, while snow gums stand at higher altitudes. The Tuross River Gorge and the Brogo Wilderness Area lie within the park.

Wadbilliga lies in a remote part of south-eastern New South Wales that saw little European settlement, so much of the park remains close to its natural state. In recent decades the area was brought under protection and deliberately left unaltered. The Wadbilliga Track, a four-wheel-drive route climbing the escarpment from east to west, is the main way into the high country.

The name Wadbilliga comes from the Wadbilliga Track, the four-wheel-drive route that climbs the escarpment from east to west; the track is the park's main way in. The area saw little European settlement, and in recent decades it has been deliberately left in a natural state. Visitors today come for overnight wilderness walking and camping, and the Brogo Wilderness Area and Tuross River Gorge are the usual destinations.

Access is via the Wadbilliga Track, a four-wheel-drive road that climbs the escarpment from east to west; the nearest towns are Cobargo and Narooma to the east and Cooma to the west. Overnight camping and wilderness walking are only for the most experienced and well-prepared visitors. Summer averages 8 °C to 23 °C, winter -3 °C to 10 °C, and the terrain ranges from 15 m to 1335 m in elevation.

Wadbilliga holds one of Australia's largest populations of the greater glider, a gliding possum that depends on old hollow-bearing trees. The park also shelters vulnerable spotted-tailed quolls and three owl species: powerful, masked and sooty. The Wadbilliga Track climbs the escarpment from east to west as a four-wheel-drive route.