In this paper a formal framework that accounts for social order within a multi-agent system based on organizational and normative concepts is presented. The fundamental building blocks of multi-agent systems are social agents whose structure can be formally characterized in terms of roles and relationships between them including authority relations. Social agents are bound together via commitments and different types of social agents may be bound by commitments in different ways. Agents are autonomous and may decide to deviate from prescribed behaviour and violate their commitments and obligations, but as a consequence they may have to face the sanctions as a result of the other agents exercising their rights.