Separation of powers is a political doctrine originating in the writings of Charles de Secondat, Baron de Montesquieu in The Spirit of the Laws, in which he argued for a constitutional government with three separate branches, each of which would have defined authority to check the powers of the others.

The separation of powers in Australia is the division of the institutions of the Australian government into legislative, executive and judicial branches.

governed by Constitution of the Republic of Singapore, which splits the power to govern the country between three branches of government – the parliament, which makes laws; the executive, which executes them; and the judiciary, which enforces them.

The concept of the separation of powers has been applied to the United Kingdom and the nature of its executive (UK government, Scottish Government, Welsh Government and Northern Ireland Executive), judicial (England and Wales, Scotland and Northern Ireland) and legislative (UK Parliament, Scottish Parliament, Senedd Cymru and Northern Ireland Assembly) functions.