Recently, there has been a growing interest in the development of collaborative relationships between organizations. Much attention has been given to how organizations 'expand the pie' of benefits between them; however, there is little that addresses the ensuing issue -how organizations divide the expanded pie. This research examines the relational impact of pie sharing in complex collaboration contexts marked by uncertainty in resources and outputs, information asymmetries, intangible aspects, and noncomparable factors and processes. A conceptual framework is developed that examines how the use of equity and equality sharing principles in conjunction with various resource and organizational conditions can be used to systematically impact relational outcomes. Survey results of 300 R&D managers, scientists, and engineers indicate that sharing principles can have a positive or negative effect on the relationship depending on the type of sharing principle used, and the characteristics of the resources and organizations. In particular, sharing processes should be responsive to the goals of the collaboration. The results underscore the strategic nature of the sharing phenomenon as well as the importance of relational concerns in complex and uncertain interorganizational settings.