This study develops and then tests an expanded conceptual framework for understanding relational customer--supplier exchanges. The explanatory power of transaction cost economics and resource dependence theory is examined, first individually, and then the theories are unified to provide a more comprehensive model for understanding of firms' decisions to pursue relational exchanges. Regression analyses performed on data from 372 pulp, paper, and paperboard mills indicate that the combined framework provides a better explanation of customer choices than either theory individually. Implications and future research are discussed. Copyright 2006, Oxford University Press.