Known informally as the Australian Naval Ensign, the Australian White Ensign is the official flag of the Royal Australian Navy. It is based on the Australian national flag which itself is an Australian Blue Ensign. Flown by HMA Ships and Submarines as a jack, the field is reversed to white with the Commonwealth Star and Southern Cross reversed to blue. The White ensign began officially flying on March 1, 1967.

The Royal Australian Navy initially flew the British White Ensign from the stern of her ships under the direction of the British Admiralty. In 1909, the Dominions of Australia and Canada proposed that a White Ensign defaced with a local national symbol would be more appropriate for use by the Dominion navies. The Admiralty insisted that the national flag could be flown from the jack staff at the bow, buy the British Naval flag would continue to fly from the stern.

In 1965, Australian forces joined the Vietnam War without the assistance or participation of the British upon which a Member of Parliament questioned the appropriateness of using the ensign of another country. It was then reported in parliament that the Navy was already looking for a distinctly Australian ensign. Upon recommendation from the Naval Board, the Government introduced a new Naval Ensign based on the Australian Ensign. It was granted Royal Assent on November 7th, 1966 and was commissioned into service on March 1st of the following year.