The Constitution of South Africa is the supreme law of the country. It provides the legal foundation for the existence of the Republic of South Africa, sets out the rights and duties of the citizens of South Africa, and defines the structure of the Government of South Africa. The current Constitution of South Africa was adopted by the Constitutional Assembly on 11 October 1996.

South Africa is a federal parliamentary representative democratic republic, wherein the President of South Africa, elected by parliament, is the head of government, and of a multi-party system. Executive power is exercised by the government. Legislative power is vested in both the government and the two chambers of Parliament, the Council of Provinces and the National Assembly. The Judiciary is independent of the executive and the legislature. Government is three-tiered, with representatives being elected at the national, provincial and local levels. South Africans also elect provincial legislatures which govern in respect of each of the country's nine provinces.

The President of the Republic of South Africa is the head of state and head of government under South Africa's Constitution.  The President is elected by members of the National Assembly, the lower house of Parliament, usually being the leader of the largest party, which has been the African National Congress since the first non-racial elections were held on 27 April 1994. The first President to be elected under the new Constitution was Nelson Mandela, who was succeeded by Thabo Mbeki in 1999, followed by Kgalema Motlanthe in September 2008,  Jacob Zuma in May 2009 and Cyril Ramaphosa in 2018. In §5, section 88, the Constitution also limits the President's time in office to two terms. Presidents are elected after each parliamentary election, giving presidents a term of office of between five and ten years.