History and ethnography show us that, across societies of the past and present, gambling varies considerably with respect to its organization, social meanings, and how it is regarded in moral terms. This paper presents a basic scheme for analyzing the relationship between gambling and society. A theoretical starting point is that reciprocity is fundamental to social and economic systems. An anthropological theory of exchange systems makes a broad distinction between a structural dimension (generalized versus balanced reciprocity) and a normative dimension (from voluntary to involuntary). A model of four basic forms of reciprocity, each having a characteristic exchange mode and morality, can thus be constructed. Gambling is here understood as an exchange system embedded in the reciprocal orders of society and having a necessary relationship to these; it can take on the characteristics of such an order or it can be regarded as conflicting with it. Much of the variation in the form and morality of gambling therefore emerges as systematic and explainable by a theory of forms of reciprocal exchange.