Cooperative norms are a critical governance mechanism of the buyer-supplier relationship. Prior studies generally assume that cooperative norms are pre-existing and utilize norms as an antecedent to other constructs. Little attention has been paid to the antecedents of the decision to develop cooperative norms. In this paper, we draw upon transaction cost economics and resource dependence theory to develop a model that depicts the key factors that determine cooperative norms. Based on the results derived from an empirical study of 278 Chinese companies, we find that these factors significantly impact cooperative norms. The study also reveals that cooperative norms positively influence suppliers' performance, which subsequently affects buyers' satisfaction.