The intellectual capital of the firm—an intangible asset embedded in the knowledge and expertise of a firm’s employees—is increasingly recognized as a source of sustainable competitive advantage. The establishment of virtual communities is among the most common approaches toward knowledge management adopted within firms. Such communities provide contexts where individuals within firms can come together, bound by shared roles, bases of expertise, or passion for specific topics, and interact. Virtual communities are recognized as important contributors to both the development of social networks among individuals but also individual performance and firm performance. This chapter provides a synthesis of prior work on the topic and highlights the key contributions of different streams of research on virtual communities. It also suggests a variety of directions for future research.