Absolute monarchy is a form of monarchy in which the monarch rules in their own right or power. In an absolute monarchy, the king or queen is by no means limited and has absolute power, though a limited constitution may exist in some countries. These are often hereditary monarchies. On the other hand, in constitutional monarchies, in which the authority of the head of state is also bound or restricted by the constitution, a legislature, or unwritten customs, the king or queen is not the only one to decide, and their entourage also exercises power, mainly the prime minister.

Absolute monarchy originally emerged in Europe after the social upheaval of the Black Death and Renaissance, and represented a reaction by monarchs to create a centralised state against the counter-balancing forces of Medieval society (feudal fragmentation, municipal corporations, etc.). Originally associated with the prestigious Duchy of Burgundy, it later spread as a model to centralize the varied territories of the Kingdom of Spain and the Kingdom of France. The absolutist system of government saw its high point during the late 16th and the 17th Century, associated with a more autocratic form of rule under figures such as Louis XIV of France, Philip II of Spain, and Charles I of England. Absolutism declined substantially, first following the French Revolution, and later after World War I, both of which led to the popularization of theories of government based on the notion of popular sovereignty. It did however provide a foundation for the newer political theories and movements that emerged to oppose liberal-democracy, such as Legitimism and Carlism in the early 19th Century, or "integral nationalism" in the early 20th century.

Absolute monarchies include Brunei, Eswatini, Oman, Saudi Arabia, Vatican City, and the individual emirates composing the United Arab Emirates, which itself is a federation of such monarchies – a federal monarchy.