The aim of this study is to develop an understanding of the factors influencing participants’ knowledge-sharing in an electronic network of practice. The study builds on a theoretical framework derived from the theory of reasoned action and theories of social capital and social exchange. A model of knowledge sharing in an electronic network of practice has been developed based on this framework, which attempts to integrate factors validated through recent empirical studies (Kankanhalli et al., 2005; Wasko and Faraj, 2005; Bock et al., 2005). The model that considers the factors influencing the knowledge contributor and the knowledge seeker has been empirically tested using a survey in the Financial Management Community of Practice (COP) in the USAF Portal. Figure 1 shows the research model adopted for the study, which incorporates constructs from social exchange theory and social capital theory. Data were collected from members of the Financial Management (FM) Communities of Practice (COP) on the AF portal. Partial least squares (PLS) was chosen as the structural equation analysis method to the test the hypotheses. The study demonstrated that experience in the profession influenced the amount of contribution, but that self-rated expertise did not. The findings indicate that relational capital may not be as important to usage, but it is strongly related to the intention to share knowledge. The study also indicated that commitment to the community of practice was not a factor in knowledge contribution. Concerning anticipated extrinsic benefits, the results show that individuals are not motivated by these types of rewards whether monetary in nature or reputation-based. The hypothesis regarding the sense of self-worth through the intention to share knowledge was not supported. Secondly, the results showed that the anticipated loss of knowledge power that occurs when an individual shares personal knowledge, did not influence an individual’s intention to share knowledge in the COP. Finally, an individual’s codification effort indicated only a relationship with number of messages posted. The results provide some evidence that cognitive social capital influences intention to share knowledge.