Sense of community (SoC) in communities of practice (CoP) seems to play a similar role to that of group cohesion in small groups: Both sustain participants' knowledge sharing, which in turn substantiates the socio-cognitive structures that make up the CoP such as scholar identities, practical repertoires in research and teaching or relationships between colleagues. However, empirical evidence of relationships between SoC and other CoP variables is scarce. A correlation study among German and Romanian scholars (N = 136) investigates predictors and effects of the social component of SoC (SoC-S) in academia. A conceptual model is validated, displaying CoP members' socio-emotional interpersonal knowledge as the strongest predictor of SoC-S and of knowledge sharing acceptance. Further, SoC-S significantly mediates the effect of time and centrality in CoP on knowledge sharing acceptance. The model explains a relatively large part of the variance of SoC-S (27 %) and of knowledge sharing acceptance (33 %). For academic practice, the study emphasizes the importance of SoC and interpersonal knowledge in academic communities as major factors of community building and knowledge sharing motivation.