The Australian Army Reserve is a collective name given to the reserve units of the Australian Army. Since the Federation of Australia in 1901, the reserve military force has been known by many names, including the Citizens Forces, the Citizen Military Forces, the Militia and, unofficially, the Australian Military Forces. In 1980, however, the current name—Australian Army Reserve—was officially adopted, and it now consists of a number of components based around the level of commitment and training obligation that its members are required to meet.

A military reserve force is a military organization whose members (reservists) have military and civilian occupations. They are not normally kept under arms, and their main role is to be available when their military requires additional manpower. Reserve forces are generally considered part of a permanent standing body of armed forces, and allow a nation to reduce its peacetime military expenditures and maintain a force prepared for war. During peacetime, reservists typically serve part-time alongside a civilian job, although most reserve forces have a significant permanent full-time component as well. Reservists may be deployed for weeks or months-long missions during peacetime to support specific operations. During wartime, reservists may be kept in service for months or years at a time, although typically not for as long as active duty soldiers.