The Order of Australia is the only Australian order of chivalry. It was established on 14 February 1975 by Elizabeth II, Queen of Australia, to recognise Australian citizens and other persons for achievement, meritorious service, or for both. At that time, Companion of the Order of Australia was the highest of three grades of the order (companion, officer, member).
On 24 May 1976, the grade of Knight or Dame of the Order was established, displacing companion as the highest grade. On 3 June 1986, the knight/dame grade was abolished, and companion was once again the highest grade.
On 25 March 2014, the knight/dame grade was re-established, companion once again being relegated to the second highest grade of the order. The knight/dame grade was again abolished on 2 November 2015.