Holsworthy is a suburb in south-western Sydney, in the state of New South Wales, Australia 31 kilometres south-west of the Sydney central business district, in the local government area of the City of Liverpool.

Holsworthy military base is an Australian Army military barracks, located in the Heathcote National Park in Holsworthy approximately 25 km (16 mi) from the central business district, in south-western Sydney, New South Wales, Australia. The barracks is part of the Holsworthy military reserve, which is 22,000 ha (54,000-acre) training area and artillery range for the Australian Army, established in the 1880s and been in active use since World War I. Following World War II, it became a major base for the permanent component of the Australian Army in New South Wales. Holsworthy Military Airport is also located in the reserve. Activities carried out on the base include the use of firing ranges, chemical weapons testing, fire training, vehicle maintenance, and bulk chemical storage and distribution from numerous above ground and underground storage tanks.