Formal control and trust are two typical governance mechanisms employed to safeguard business transactions. Yet the effectiveness of each mechanism for firm relationship outcomes remains unclear. Some relevant literature suggests that formal control and trust simultaneously can help secure transactions, whereas other research argues the two control mechanisms can substitute for each other. This study applies social embeddedness theory and differentiates strong tie from weak tie relationships. In so doing, it reveals the role of strong versus weak social ties in leading to parallel conclusions about the relationship between formal control and trust and their effects on relationship outcomes. On the basis of empirical tests in a Chinese marketing channels context, this study finds that the joint effects of formal control and trust on governing transactions depends on the relational tie that the focal partners share. Specifically, formal control and trust complement each other only in weak tie relations. On the basis of this new perspective, the authors offer theoretical and managerial implications for managing interfirm governance mechanisms in transitional economies such as China. © 2010 Elsevier Inc.