How do internal resources, relational resources, and relational mechanisms determine knowledge transfer among crucial partners in clusters? We analyze a sample of Spanish footwear manufacturers to distinguish the relative impact of internal resources, intra-cluster relationships, and governance (including power asymmetries) on knowledge transfer between leading firms and their partners. Internal resources appear to be highly beneficial for knowledge transfer among partners, while intra-cluster relationships diminish such transmissions. The governance structure of the partnership also appears to have an important influence on knowledge transfer between leading organizations and their suppliers. These results suggest valuable implications for practitioners, researchers, and policy makers at both the firm and meso levels.