Girl Guides Australia (GGA) is the national Girl Guiding organisation in Australia. Its mission is to empower "girls and young women to discover their potential as leaders of their world". Membership is open to all girls and young women from all cultures, faiths and traditions. Guiding groups formed in Australia as early as 1909, and by 1920 Girl Guide Associations had been formed in six states. In 1926 the State Associations federated and formed a national organization which became a founding member of the World Association of Girl Guides and Girl Scouts in 1928. It still operates as a federated structure made up of six state-based Guiding organisations. It has roughly 19,000 members (as of 2021) including adult and youth members. Over a million Australian women are or have been Guides. The Girl Guide emblem incorporates the Commonwealth Star.

In July 2012, the Guide Promise was updated, along with the Guide Law (as below), to better reflect modern society and the perspective of current day Guides. These changes were a result of comprehensive consultation with Girl Guides throughout Australia through the Promise and Law Review.

Notable changes include the removal of explicit reference to God, instead replaced by "my beliefs", and removing reference to the Queen. This updated promise was ratified by the World Association of Girl Guides and Girl Scouts on 3 July 2012 and now stands as below:

I promise that I will do my best
To be true to myself and develop my beliefs
To serve my community and Australia
And live by the Guide Law.

For many years, the Guide Promise closely resembled that of Girlguiding UK:

I promise that I will do my best:
To do my duty to God,
to serve the Queen and my country,
To help other people, and
To keep the Guide Law.

The Girl Guides Australia Board in May 2010, passed a recommendation that Members may opt to use an alternative to the current Promise:

I promise that I will do my best:
to do my duty to God and my country;
to help other people; and
to keep the Guide Law.