Research on how social capital influences knowledge transfer and subsequent organizational outcomes is burgeoning, and yet our understanding of how they relate remains rather unclear. Although conceptual and qualitative reviews have emerged, no study has explicitly attempted to examine the mediating role of knowledge transfer. In this paper, we develop moderated mediation model on social capital, knowledge transfer and performance. We distinguish between structural and relational capital, and argue that knowledge transfer is a necessary step in converting potential benefits of social capital into organizational outcomes. We also demonstrate how organizational boundaries (i.e. intra- and interorganizational context), and environmental context (i.e. the type of industry) moderate the relationships studied. By aggregating and consolidating existing research, our study not only reveals new insights into how social capital influences organizational knowledge transfer and performance, but also provides meaningful directions for future research.