Key account management (KAM) supports the profitability and financial sustainability of firms in business-to-business markets. It also attracts considerable academic research. However, KAM research remains largely atheoretical and lacking in conceptual foundations. This paper argues for an organizational-level, resource-based view of KAM. Using a systematic approach, the authors review the KAM literature to identify the critical resources and capabilities that underpin strategic KAM. The analysis synthesizes and integrates previous research on KAM applying a resource-based lens to reveal that strategic KAM comprises complex portfolios of resources and capabilities that constitute a source of competitive advantage. The authors discuss the theoretical and practical implications of this unique view of KAM and identify directions for further research.