Authority is commonly understood as the legitimate power of a person or group of other people. In a civil state, authority may be practiced by legislative, executive, and judicial branches of government, each of which has authority and is an authority. The term "authority" has multiple nuances and distinctions within various academic fields ranging from sociology to political science.

The term authority identifies the political legitimacy, which grants and justifies rulers' right to exercise the power of government; and the term power identifies the ability to accomplish an authorized goal, either by compliance or by obedience; hence, authority is the power to make decisions and the legitimacy to make such legal decisions and order their execution.

Ancient understandings of authority trace back to Rome and draw later from Catholic (Thomistic) thought and other traditional understandings. In more modern terms, forms of authority include transitional authority (exhibited in, for example, Cambodia), public authority in the form of popular power, and, in more administrative terms, bureaucratic or managerial techniques. In terms of bureaucratic governance, one limitation of the governmental agents of the executive branch, as outlined by George A. Krause, is that they are not as close to the popular will as elected representatives are. The claims of authority can extend to national or individual sovereignty, which is broadly or provisionally understood as a claim to political authority that is legitimated.

Historical applications of authority in political terms include the formation of the city-state of Geneva, and experimental treatises involving the topic of authority in relation to education include Emile, or On Education by Jean-Jacques Rousseau. As David Laitin defines, authority is a key concept to be defined in determining the range and role of political theory, science and inquiry.

There have been several contributions to the debate of political authority. Among others, Hannah Arendt, Carl Joachim Friedrich, Thomas Hobbes, Alexandre Kojève and Carl Schmitt have provided some of the most influential texts.

In European political philosophy, the jurisdiction of political authority, the location of sovereignty, the balancing of notions of freedom and authority, and the requirements of political obligations have been core questions from the time of Plato and Aristotle to the present. Most democratic societies are engaged in an ongoing discussion regarding the legitimate extent of the exercise of governmental authority. In the United States, for instance, there is a prevailing belief that the political system as instituted by the Founding Fathers should accord the populace as much freedom as reasonable; that government should limit its authority accordingly, known as limited government.

Political anarchism is a philosophy which rejects the legitimacy of political authority and adherence to any form of sovereign rule or autonomy of a nation-state. An argument for political anarchy is made by Michael Huemer in his book The Problem of Political Authority. On the other side, one of the main arguments for the legitimacy of the state is some form of the social contract theory developed by Thomas Hobbes in his 1668 book, Leviathan, or by Jean-Jacques Rousseau in his political writings on the social contract.

In sociology, authority is the legitimate or socially approved power which one person or a group possesses and practices over another. The element of legitimacy is vital to the notion of authority and is the main means by which authority is distinguished from the more general concept of power.