Findings from prior research on the relationship between a team’s social network architecture and team innovation have been inconclusive. Integrating social network theory with input-process-output models of team innovation, our research aims to reconcile the mixed findings in the literature by introducing a novel process perspective as well as highlighting a relevant contingency factor to untangle the team social capital – team innovation link. We propose that team social capital, operationalized as bridging and bonding social capital, negatively influences team innovation via team proportional task conflict, which is the level of task conflict teams experience proportional to the general level of team conflict (i.e., task, relationship, and process conflict). In addition, we expected group and differentiated individual-focused transformational leadership (TFL) to buffer the negative indirect effect of team social capital on team innovation via team proportional task conflict. Results from time-lagged data collected from research and development (R&D) teams in Iraq revealed that teams with bonding and bridging social capital are less innovative because they experience less proportional task conflict. Furthermore, group-focused TFL buffered the negative indirect relationship of team bridging social capital on team innovation via proportional task conflict. Theoretical and practical implications of these findings are discussed.