Much of the literature on inter-organizational relations assumes that firms operate as relatively autonomous and cohesive units that are (1) unimpeded by wider institutional norms governing the industry as a whole, and (2) allow little or no role for the boundary spanning agents who oversee and monitor 'contracts' on a daily basis. This perspective is not surprising given that so many studies rely solely on questionnaires completed by a single respondent within one or more of the organizations. Nor has there been much recognition of the dynamic interplay between forces at the institutional, organizational and interpersonal levels. In order to address these issues, we propose a framework that explicitly focuses on forces at these three levels, as well as the interplay between them, in order to analyse how and why inter-organizational relations take the forms they do. We argue that trusting, OCR-type relations are more likely to be produced and reproduced when there are strong institutional forces promoting common obligations on both parties, and there is a relative mutuality of power relations between the organizations. However, because the contract is maintained by boundary spanning agents, agreed norms at the institutional and organizational levels are a necessary but not sufficient factor for OCR to develop. Conversely, in the absence of these forces, there is less incentive for either organization to establish and maintain close interpersonal relations, and indeed ACR-type, distant relations may be beneficial for organizations and individuals that wish to dispense with existing contracts.