In this study, the authors investigate the relationship of structure and process with partnership satisfaction in interfirm cooperation. In particular, they focus on the less-researched aspect of process. Structure refers to the ex-ante transaction cost-based and partner characteristics of the partnership, whereas process refers to the action pattern that unfolds during the cooperation. Two structural factors, asset specificity and partner reputation, are first examined. Informed by an action approach, they further identify three important aspects of the cooperation process, namely, action acquiescence, action simplicity, and action reciprocity. Their relationships with partnership satisfaction are tested on a sample of 230 architect-contractor partnerships in Hong Kong. The results revealed that action acquiescence and action simplicity explained significant variance in partnership satisfaction above and beyond those explained by the two structural factors.