The Australian Defence Medal was established on 20 March 2006

It recognises qualifying efficient service of current and former Australian Defence Force (ADF) Regular and Reserve personnel, including National Servicemen, who have served since the end of World War II. The eligibility criteria requires completion of an initial enlistment period or four years service, whichever is the lesser. The criteria also includes those who could not serve the four-year qualifying period or complete an initial enlistment period.