The use of strategic alliances is growing as acquisitions and mergers often under-perform expectations. This research looks at the literature on strategic alliances to gain an understanding of the rationale for strategic alliances, organizational propensity to enter into strategic alliances and their effect on sustainable competitive advantage. The methodology is qualitative, based on twelve case studies of organizations, with five out-performing the industry and five under-performing. The cases are structured around the value chain and modified grounded theory is used to analyze the data and to gain a deeper understanding of the phenomenon. A wider range of reasons for entering alliances is substantiated and the theory concerning organizational propensity to enter into strategic alliances is supported. Strategic alliances are being used to perform many value chain functions as organizations are lacking in both capabilities and resources. These are being accessed by using strategic alliances in the search for differentiation, sustainable competitive advantage and superior performance.