Self-sufficiency refers to the state of not requiring any outside aid, support, or (in hardline cases) interaction, for survival; it is therefore a type of extreme personal autonomy.

Self-sufficiency is usually applied to varieties of sustainable living in which nothing is consumed outside of what is produced by the self-sufficient individuals. Examples of attempts at self-sufficiency in North America include voluntary simplicity, Luddism, homesteading, survivalism, and the Back to the land movement.

Practices that enable or aid self-sufficiency include autonomous building, permaculture, sustainable agriculture, and renewable energy.

The existence of an effectively closed system makes self-sufficiency a necessity for any form of space colonization. An extreme experimental example of self-sufficiency could therefore be said to be the Biosphere 2 project.

The term is also applied to more limited forms of self-sufficiency, for example growing one's own food or becoming economically independent of state subsidies or (in the case of larger political entities) foreign aid.