A head of state (or chief of state) is the public persona who officially embodies a state in its unity and legitimacy. Depending on the country's form of government and separation of powers, the head of state may be a ceremonial figurehead or concurrently the head of government and more (such as the president of the United States, who is also commander-in-chief of the United States Armed Forces).

In a parliamentary system, such as the United Kingdom or India, the head of state usually has mostly ceremonial powers, with a separate head of government. However, in some parliamentary systems, like South Africa, there is an executive president that is both head of state and head of government. Likewise, in some parliamentary systems the head of state is not the head of government, but still has significant powers, for example Morocco. In contrast, a semi-presidential system, such as France, has both heads of state and government as the de facto leaders of the nation (in practice they divide the leadership of the nation between themselves). Meanwhile, in presidential systems, the head of state is also the head of government. In one-party ruling communist states, the position of president has no tangible powers by itself, however, since such a head of state, as a matter of custom, simultaneously holds the post of General Secretary of the Communist Party, they are the executive leader with their powers deriving from their status of being the party leader, rather than the office of president.

Former French president Charles de Gaulle, while developing the current Constitution of France (1958), said that the head of state should embody l'esprit de la nation ("the spirit of the nation").