Anarcho-capitalism (colloquially: ancap or an-cap) is a political philosophy and economic theory that advocates for the abolition of centralized states in favor of stateless societies, where systems of private property are enforced by private agencies. Anarcho-capitalists argue that society can self-regulate and civilize through the voluntary exchange of goods and services. This would ideally result in a voluntary society based on concepts such as the non-aggression principle, free markets, and self-ownership. In the absence of statute, private defence agencies and/or insurance companies would operate competitively in a market and fulfill the roles of courts and the police, similar to a state apparatus.

According to its proponents, various historical theorists have espoused philosophies similar to anarcho-capitalism. While the earliest extant attestation of "anarchocapitalism" [sic] is in Karl Hess's essay "The Death of Politics" published by Playboy in March 1969, American economist Murray Rothbard was credited with coining the terms anarcho-capitalist and anarcho-capitalism in 1971. A leading figure in the 20th-century American libertarian movement, Rothbard synthesized elements from the Austrian School, classical liberalism and 19th-century American individualist anarchists and mutualists Lysander Spooner and Benjamin Tucker, while rejecting the labour theory of value. Rothbard's anarcho-capitalist society would operate under a mutually agreed-upon "legal code which would be generally accepted, and which the courts would pledge themselves to follow". This legal code would recognize contracts between individuals, private property, self-ownership and tort law in keeping with the non-aggression principle. Unlike a state, enforcement measures would only apply to those who initiated force or fraud. Rothbard views the power of the state as unjustified, arguing that it violates individual rights and reduces prosperity, and creates social and economic problems.

Anarcho-capitalists and right-libertarians cite several historical precedents of what they believe to be examples of quasi-anarcho-capitalism, including the Republic of Cospaia, Acadia, Anglo-Saxon England, Medieval Iceland, the American Old West, Gaelic Ireland, and merchant law, admiralty law, and early common law.

Anarcho-capitalism is distinguished from Minarchism, which advocates a minimal governing body (typically a night-watchman state limited to protecting individuals from aggression and enforcing private property) and from objectivism (which is a broader philosophy advocating a limited role, yet unlimited size, of said government). Anarcho-capitalists consider themselves to be anarchists despite supporting private property and private institutions.

Anarcho-capitalism developed from Austrian School-neoliberalism and individualist anarchism. Almost all anarchist movements do not consider anarcho-capitalism to be anarchist because it lacks the historically central anti-capitalist emphasis of anarchism. They also argue that anarchism is incompatible with capitalist structures. According to several scholars, Anarcho-capitalism lies outside the tradition of the vast majority of anarchist schools of thought and is more closely affiliated with capitalism, right-libertarianism and neoliberalism. Traditionally, anarchists oppose and reject capitalism, and consider "anarcho-capitalism" to be a contradiction in terms, although anarcho-capitalists and some right-libertarians consider anarcho-capitalism to be a form of anarchism, with others considering it the only form.

According to the Encyclopædia Britannica:

Anarcho-capitalism challenges other forms of anarchism by supporting private property and private institutions with significant economic power.

Anarcho-capitalism is occasionally seen as part of the New Right.