Although prior research has realized that a transactive memory system (TMS, a group-level socio-cognitive structure) benefits team performance, few studies have explicitly explored the knowledge management (KM) essence of the TMS-team performance relationship. Further, scholars have highlighted the necessity of examining TMS dimensions (i.e., specialization, credibility, and coordination) due to their theoretical distinction. Based on TMS literature and the organizational learning perspective, this study investigates how TMS dimensions relate to knowledge transfer (i.e., a subprocess of team learning), thereby influencing team performance in real organizations. We also proposed the mediating effect of knowledge transfer. The research model was tested through a field survey of 61 Chinese knowledge teams from various industries and companies. Research findings demonstrated that the associations of specialization and credibility with knowledge transfer were more significant than that of coordination. Moreover, knowledge transfer predicted the variation in team performance and fully mediated the effect of specialization and credibility on team performance. Our research findings advance the current understanding of the underlying mechanism of the TMS–team performance relationship and provide implications for academics and practitioners.