The Government of Singapore is defined by the Constitution of the Republic of Singapore to consist of the President and the Executive. Executive authority of Singapore is vested in the President but exercised on the advice of the Cabinet led by the Prime Minister. The President, acting as the Head of State, may only act in their discretion in appointing the Prime Minister, acting as the Head of Government; as well as withholding consent for the dissolution of Parliament; along with performing key checks on the Government in addition to the ceremonial duties of the Head of State inherited from the Westminster system. The Cabinet, consisting of the Prime Minister and ministers appointed by the President on the Prime Minister's advice, is responsible for heading the Executive through ministries and other statutory boards. At the end of the term or at any time during the term, once the President has consented to a request made by the Prime Minister to dissolve Parliament, Parliamentary General Elections are held to elect members of Parliament for a new term. The President, in their discretion, then appoints a Prime Minister who is a member of Parliament representing any political party or coalition of political parties who in their judgement is likely to command the confidence of the majority of the members of Parliament. The Prime Minister then forms the Government and, along with the Cabinet, sets the general direction and control of the Government for the next term.

The Constitution of the Republic of Singapore is the supreme law of Singapore. A written constitution, the text which took effect on 9 August 1965 is derived from the Constitution of the State of Singapore 1963, provisions of the Federal Constitution of Malaysia made applicable to Singapore by the Republic of Singapore Independence Act 1965, and the Republic of Singapore Independence Act itself. The text of the Constitution is one of the legally binding sources of constitutional law in Singapore, the others being judicial interpretations of the Constitution, and certain other statutes. Non-binding sources are influences on constitutional law such as soft law, constitutional conventions, and public international law.