The Defence Medal is awarded for six months service in a prescribed non-operational area subject to enemy air attack or closely threatened, in Australia and overseas, or for 12 months service in non-prescribed non-operational areas.
Within Australia, the area is the Northern Territory, north of 14 degrees 30 minutes south, and the Torres Strait Islands between 3 September 1939 and 2 September 1945.
Overseas service includes the Middle East, east of the Suez Canal (less the period of the Syrian Campaign) or Malaya prior to the Japanese invasion on 8 December 1941.
The medal is cupro-nickel, with the uncrowned effigy of King George VI on the obverse.
The reverse has a conventional oak tree centrally, with a crown above, with two lions counter rampart as supporters between the dates 1939 and 1945. The base of the medal reverse has the words THE DEFENCE MEDAL.
The ribbon is orange with green outer stripes, each green stripe having a black pin-stripe running down the centre. The green represents the Islands of the United Kingdom, the orange represents enemy attacks, and the black represents the blackouts.