Prospect Nature Reserve, Nature reserve and water catchment area in Western Sydney, Australia

Prospect Nature Reserve is a reserve and recreation area in Sydney's western suburbs, within Blacktown City and near the Cumberland and Fairfield boundaries. It contains the Prospect Reservoir plus picnic spots, lookouts, walking tracks and BBQ areas in Australian bush, and lies in the eastern reaches of Western Sydney Parklands.

Prospect Nature Reserve was gazetted on 28 February 2007, though its picnic grounds had already been open to the public for decades. Sydney Water owns and manages the picnic areas around Prospect Reservoir. The reserve was closed from October 2013 to July 2015 while the reservoir was upgraded at a cost of $13.7 million.

The reserve and the Eastern Creek landscape hold cultural value for the Darug people. The reserve also has scientific and educational value, and its woodland is studied as a remnant of Cumberland Plain Woodland. Hoop pines stand at the reserve entrance, a planting a visitor can spot on arrival.

The reserve lies in Blacktown City, near the Cumberland Council and Fairfield boundaries, and is reached from Prospect Highway. George Maunder Park adjoins the reservoir and holds its valve house; the lower lookout, about 85 m above sea level, has picnic tables, toilets and water. The upper lookout closed in the early 2000s and the lower one lost vehicle access in 2009.

The reserve protects the largest area of grey box woodland in the Blacktown area, mostly Shale Hills Woodland, with Shale Plains Woodland making up the rest. Only 7.6% to 11.5% of the original Cumberland Plain bushland present in 1750 survives, and less than 13% of the Cumberland Plain Woodland community remains.