Virtual communities of practice (VCoPs) are increasingly recognized as a way to generate and assimilate organizational knowledge. VCoPs extend Wenger’s (1998) concept of community of practice to the virtual world, using technologies such as web forums, wikis, blogs, email, and social networking software. The success of a VCoP as a knowledge-sharing medium depends on active and useful contribution from members. Encouraging such contribution can be a challenge for managers given the informal, low-regulation environment of a VCoP. Conventional managerial controls and incentives become less significant in motivating contribution, and more intrinsic factors come to the fore. This paper describes the theoretical roots explaining such motivation and progress represented by research applying them to online networks. Our central contention is that a unified theoretical approach, suited to the characteristics of VCoPs, is needed to guide future research. Selfdetermination theory (Ryan and Deci, 2000) is proposed as fulfilling this need.