The Flag of Australia was chosen in 1901 from entries in a worldwide design competition held following Federation. It was approved by Australian and British authorities over the next few years, although the exact specifications of the flag were changed several times both intentionally and as a result of confusion.

The current specifications were published in 1934, and in 1954 the flag became legally recognized as the "Australian National Flag". The flag is a defaced Blue Ensign: a blue field with the Union Flag in the canton (upper hoist quarter), and a large white seven-pointed star known as the Commonwealth Star in the lower hoist quarter.

The flag contains a representation of the Southern Cross constellation, made up of five white stars – one small five-pointed star and four, larger, seven-pointed stars.