Unit Colour Patches (or simply known as Colour Patches) are worn on the slouch hat in the Australian Army to indicate which unit they are from. Unit colour patches are approximately 40mm x 40mm in size and have a large variety of colours and shapes to distinguish them.
The shape of the patch indicated the Division: The First Division had a rectangular patch, the Second Division had a diamond-shaped patch, the Third Division had a horizontal oval patch, the Fourth Division had a circle, the Fifth Division had a vertical oblong patch and the Sixth Division had a verticall oval patch. 
The original series of colour patches was discontinued in 1949, and a new system was introduced in 1987 known as Series I and Series II colour patches. The Series I range are known as the 'Heritage' patches and are the pre-1949 patches maintained in a register with the Series I 'Extended' and Series II range introduced during the 1990s. Both are used in the Australian Army due to some units tracing their lineage to the 1st AIF units. The Register also includes the patches for the Royal Australian Air Force and Royal Australian Navy patches.
|Wikimedia Commons has media related to Colour Patches of the Australian Army.|
- Blackwell, Phillip (2008). Australian Army Unit Colour Patches 1987–2008. Australian Military History Publications, Australia. ISBN 0-9578280-0-4.
- Department of Defence (1993). Army Colour Patch Register 1915–1949. Canberra: Defence Centre. OCLC 35701067.
- Glyde, Keith (1999). Distinguishing Colour Patches of the Australian Military Forces 1915–1951: A Reference Guide. Claremont, Tasmania: K Glyde. ISBN 0646366408.
- Hopkins, Ronald (1978). Australian Armour. A History of the Royal Australian Armoured Corps 1927–1972. Canberra: Australian Government Publishing Service. ISBN 978-0-642-99414-1.