The Resource-Based View (RBV) of competitive advantage provides a theoretical framework from the field of strategic management for assessing the competitive advantages of family firms. The RBV isolates idiosyncratic resources that are complex intangible and dynamic within a particular firm. The bundle of resources that are distinctive to a firm as a result of family involvement are identified as the “familiness” of the firm. This approach provides a research and practice method for assessing the specific behavioral and social phenomena within a firm that provide an advantage. Using a familiness model for assessing competitive advantage overcomes many of the problems associated with the generic claim that family companies have an advantage over nonfamily companies. It also provides a unified systems perspective of family firm performance.