in the social sciences, a reaction (or the threat or promise of a reaction) by members of a social group indicating approval or disapproval of a mode of conduct and serving to enforce behavioral standards of the group. Punishment (negative sanction) and reward (positive sanction) regulate conduct in conformity with social norms (see norm). Sanctions may be diffuse—i.e., spontaneous expressions by members of the group acting as individuals—or they may be organized—i.e., actions that follow traditional and recognized procedures. Sanctions therefore include not only the organized punishments of law but also the formal rewards (e.g., honours and titles) and the informal scorn or esteem by members of a community.

In societies without formal legal institutions, such as courts of law, sanctions are often imposed directly by the wronged individual or group. Reaction is in a socially approved manner and in a form considered proportional to the injury. This may include ridiculing, duelling, injuring, seizing of property, or killing the offender or a member of his group. Among the Eskimo, for example, the appropriate punishment for a man who steals another man's wife is to be ridiculed in a nasty song made up by the injured man. Social context, as well as the kind of offense, determines the type of sanction invoked: legal, religious, and moral sanctions can all operate. A breach of norms committed within a kin group may call for religious sanctions, although the same deed involving different kin groups would invoke jural sanctions.

Sanctions, in addition to functioning as a mechanism of social control, also serve to integrate a society, affirming social beliefs and restating their validity when breached.