The Constitution of Australia is the fundamental law that governs the political structure of Australia. It is a written constitution, that establishes the country as a federation under a constitutional monarchy governed with a parliamentary system. Its eight chapters sets down the structure and powers of the three constituent parts of the federal level of government: the Parliament, the executive government and the judicature.

Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. Australia is the largest country by area in Oceania and the world's sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a megadiverse country, and its size gives it a wide variety of landscapes and climates, with deserts in the centre, tropical rainforests in the north-east, tropical savannas in the north, and mountain ranges in the south-east.