Autarky is the characteristic of self-sufficiency, usually applied to societies, communities, states, and their economic systems.

Autarky as an ideology or economic approach has been attempted by a range of political ideologies and movements, particularly leftist ones like African socialism, mutualism, war communism, communalism, swadeshi, syndicalism (especially anarcho-syndicalism), and left-wing populism, generally in an effort to build alternative economic structures or to control resources against structures a particular movement views as hostile. However, some right-wing ones, like nationalism, conservatism, and anti-globalism, along with even some centrist movements, have also adopted autarky, generally on a more limited scale, to develop a particular industry, to gain independence from other national entities or to preserve part of an existing social order.

Proponents of autarky have argued for national self-sufficiency to reduce foreign economic, political, and cultural influences, and to promote international peace. However, economists are generally supportive of free trade; there is broad consensus among economists that protectionism has a negative effect on economic growth and economic welfare while free trade and the reduction of trade barriers has a positive effect on economic growth and economic stability.

Autarky may be a policy of a state or some other type of entity when it seeks to be self-sufficient as a whole, but it also can be limited to a narrow field such as possession of a key raw material. Some countries have a policy of autarky with respect to foodstuffs (such as South Korea), and water for national-security reasons. Autarky can result from economic isolation or from external circumstances in which a state or other entity reverts to localized production when it lacks currency or excess production to trade with the outside world.

The word autarky is from the Ancient Greek word Greek: αὐτάρκεια, which means "self-sufficiency" (derived from αὐτο-, "self", and ἀρκέω, "to suffice"). In Stoicism the concept of autarky represents independence from anything external, including independence from personal relationships, so as to immune one from vagaries of fortune. The Stoic sage is autarkic by being dependent only on his own virtue. In Epicureanism the concept of autarky represents having the fewest possible requirements for living a life of pleasure, free of pain (aponia).

Lexico, whose content is provided by the same publisher as that of the Oxford English Dictionary, says that autarky is a variant spelling of and pronounced the same as autarchy and that autarchy is another term for autocracy.

Early state societies that can be regarded as autarkic include nomadic pastoralism and palace economy, though over time these tend towards becoming less self-sufficient and more interconnected. The late Bronze Age, for example, saw formerly self-sufficient palace economies rely more heavily on trade, which may have been a contributing factor to the eventual Bronze Age Collapse when multiple crises hit those systems at once. After that collapse, the ideal of autarkeia formed a part of emerging Greek political culture, emphasizing economic self-sufficiency and local self-rule.

The populist Chinese philosophy of Agriculturalism, prominent in the Spring and Autumn and Warring States periods, supported egalitarian, self-sufficient societies as an antidote to rampant war and corruption.