High failure rates often observed in practice suggest that interorganizational collaborative relationships, e.g. strategic alliances, collaborative networks and collaborative supply chains, are still not well understood. This work contributes to their understanding by focusing on their nature. Based on second-order cybernetics and social systems theory, a novel model of interorganizational collaborative relationships is proposed: the Collaborative System. This model explains the following: the organizational function of these relationships; their nature and structure; their emergence and evolution; and the high failure rates observed in practice. Obeying the requirements of a good theory, the proposed model sheds new light on the understanding, research and practice of collaboration.