The executive branch of government denotes the individual or small group of individuals that act as the chief executive(s) of the state. It is composed of the top political leaders of the state. Although the primary task of the executive is to provide leadership, it also performs a variety of other functions such as the formation of public policy and ceremonial roles. The presence of an executive has long been a key element of government. The term itself is derived from the Latin term ex sequi meaning "to carry out." Most simply this is what the executive does; it carries out the operations of the political system. The executive is the founding structure of modern government, dating back to the times of the absolute monarchs. In fact, all other government bodies originally developed as tools of the executive. For example, the legislature was created merely to assist and advise these absolute rulers. However, as society has evolved, the role of these other government structures has changed substantially. For instance, modern legislatures tend to be independent from the executive and often act as a constraint upon its power.

The leadership role embodied in the executive is broken down into two components. One is known as the head of state function which entails acting as a ceremonial leader. The other is known as the head of government function which entails conducting the actual managerial functions, and attending to the political aspects, of government. Due to the differentiation between these two aspects of executive leadership, when the two are not combined in a single individual, the head of state tends to have substantially less political power than the head of government. In most instances, there exists what is known as a fused executive. This means that there is only one individual who fulfils the role of the head of state and the head of government. For example, the President occupies this position in the United States. However, in some political systems there may be a dual executive. In this instance, the roles of the head of state and the head of government are represented separately by the presence of two different individuals. For example, there is both a President and a Prime Minister in France. A benefit of this system is that the citizenry can direct their discontent or disaffection at the government and still feel a sense of loyalty to, and respect for, the state.