Firms increasingly acquire needed information technology (IT) products and services from external sources through the formation of partnerships. In spite of the ubiquity of IT outsourcing practice in today's organizations however, theoretical understanding of IT partnerships in outsourcing is limited. Extant research has largely focused on the economic or strategic aspects of IT outsourcing, using transaction cost economics (TCE) and the resource-based view (RBV) as dominant theoretical frameworks. This dissertation adopts a social perspective to examine the IT outsourcing phenomenon. It focuses on IT partnerships in transformational outsourcing relationships that are interorganizational engagements formed to rapidly and substantially improve performance at the organizational level. By synthesizing the knowledge based view of the firm with the concept of social capital, I attempt to explain how IT outsourcing relationships generate value for organizations. I argue that IT outsourcing partnerships constitute a form of social capital for the firm that chooses to outsource, that facilitates knowledge exchange and transfer. The increased knowledge stock as a result of knowledge exchange and transfer, in turn, forms the foundation for IT value, which is manifested as success in business operations and IT-enabled innovation. To empirically test the theoretical model, I surveyed 151 client firms and 79 outsourcing service providers in China. Results suggest that both social capital and knowledge acquisition are crucial to the success of IT outsourcing. Evidence from the survey responses also indicates that different aspects of social capital play different roles in the process of IT value creation. Specifically, the structural dimension (partner resource endowment) and the cognitive dimension of social capital (shared vision and shared cognition) have a strong impact on knowledge acquisition; whereas the relational dimensions of social capital (social interaction and trust) has strong direct effects on successful outcomes of IT outsourcing. This study presented evidence that helps further our understanding of the IT outsourcing phenomenon through an alternative theoretical lens, and emphasizes the value other than immediate cost-related benefits that organizations may garner through IT outsourcing partnerships.