Australians for Constitutional Monarchy (ACM) is a group that aims to preserve Australia's current constitutional monarchy, with Charles III as King of Australia. The group states that it is a non-partisan, not-for-profit organisation whose role is "To preserve, to protect and to defend our heritage: the Australian constitutional system, the role of the Crown in it and our Flag".

The monarchy of Australia is a key component of Australia's form of government, embodied by the Australian sovereign and head of state. The Australian monarchy is a constitutional one, modelled on the Westminster system of parliamentary government, while incorporating features unique to the constitution of Australia.