Although the resource-based view (RBV) is one of the most popular and fruitful areas of strategy research, it often perplexes scholars from other disciplines. Also, it is unclear whether strategy scholars themselves agree on the RBV's basic issues and premises. To clarify the contribution of the RBV, in this paper we elaborate its basic tenets and relate them to other current research on interfirm performance variance. We suggest a more expansive discussion of sustained differences among firms and thereby develop a broad theory of competitive heterogeneity. Copyright © 2003 John Wiley & Sons, Ltd.