Buyer–supplier relationships involve dyadic interactions, but there is a dearth of empirical dyadic analysis of these relationships. While relationships with a power balance between partners do exist, relationships typically occur in the context of power asymmetry. This study examines how perceptions of power use and prevailing relationship quality in dyadic relationships characterized by substantial power asymmetry affect behavioral and operational outcomes. Hierarchical regression is used to analyze data from a dyadic survey of relationships of a brand-name buying organization and its suppliers. Results indicate that power use affects partner behavior and operational performance, but the nature of the relationship dictates which power sources are most appropriate. In addition, the mediation effect of power imbalance shows that both relational and transactional factors can play an important role in supply chain exchanges.