Wetherill Park is a suburb of Sydney, in the state of New South Wales, Australia. Wetherill Park is located 34 kilometres west of the Sydney central business district, in the local government area of the City of Fairfield and is part of the Greater Western Sydney region.
The 2011 census recorded that Wetherill Park as having a resident population of 6,026. Just under half (47.5%) of these residents were born in Australia. The area is 11.2 km2. Most residents live in the south-east corner, the larger portion of the suburb being an industrial area.
Wetherill Park sits on the southern border of Prospect Reservoir.