Consumption is the using up of a resource. Discussions of human consumption of resources plays an important role in both economics and environmentalism. In Keynesian economics, "consumption" is short-hand for personal consumption expenditure and is determined by the consumption function, especially by the marginal propensity to consume. It is part of aggregate demand or effective demand.

Consumption can also be defined as "the selection, adoption, use, disposal and recycling of goods and services", as opposed tho their design, production and marketing.

Studies of consumption investigate how and why society and individuals consume goods and services, and how this affects society and human relationships. Contemporary studies focus on meanings, role of consumption in indentity making, and the 'consumer' society. Traditionally, consumption was seen as rather unimportant compared to production, and the political and economic issues surrounding it. With the development of a consumer society, increasing consumer power in the market place, the growth in marketing, advertising, sophisticated consumers, ethical consumption etc, it is recognised as central to modern life. Sociology of consumption has moved well beyond Velben's early work on 'conspicuous' consumption. Current theories investigate the role of economic and cultural factors in constraining consumption, as development of an approach that sees consumers as 'victims' of producers and their social situation. A counter theory highlights the subversive aspects of consumption, with consumers buying and using goods, places etc in ways unintended by the producers. Examples include city squares turned to skateboard parks, and music sharing on the internet.

Studies of consumption come from a variety of backgrounds. Consumer studies attempt to help marketing; user research aims to improve product design; feminist studies highlights the importance of women as consumers, and particularly the role of the domestic arena in consumption; Media studies try to understand the consumption of media products such as television and video games. Critical Theory is an important influence on contemporary studies, as consumption is central to contemporary culture.

Studying consumption can be done through traditional survey methods, or various ethnographic techniques. Consumption studies are difficult because they involve investigating everyday life situations, rather than formalised settings such as the workplace.

Well known studies of consumption include those by Pierre Bourdieu and Daniel Miller. Favourite topics include studies of food, new technologies, fashion items, and television.

See also: List of things which are neither production nor consumption

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Consumption is also an archaic name for the disease tuberculosis, presumably because, prior to the age of modern antibiotics, often it would seem that the disease was consuming patients from within as they coughed up blood.