The notion of convention is a core notion of the interdisciplinary and in-ternational movement of economics and sociology of conventions (in short EC/SC). This chapter presents developments, models and different notions of the name giving concept of “convention”. EC/SC can be conceived as a complex pragmatist institutionalism, which explains coordination, evaluation and interpretation in situations by referring to conventions. This way, conventions can be regarded as institutional logics for the valuation or valorization of goods, actions and persons. An early application of EC/SC has been the sociology of quantification and categorization, where conventions are analyzed as the basis for measurement. EC/SC has built up its perspective on conventions on two foregoing notions, which were introduced by Keynes and Lewis. EC/SC assumes that real situations are governed by a plurality of co-existing conventions. Therefore, a set of models have been worked out, which systematize conventions as logics of evaluation, valuation and interpretation. This chapter presents how EC/SC approaches the stability and dynamics of conventions and concludes by pointing to EC/SC as a contemporary reconciliation of pragmatism and structuralism.