Given the nested nature of work teams, this study distinguishes social capital between team-levels and individual-levels to investigate their effects on individual knowledge sharing in work teams. A survey was conducted to test the hypotheses involving 343 participants who were nested in 47 knowledge-intensive teams across 9 Chinese organizations. Our results reveal that social capital at different levels conjointly influences individuals' sharing of their explicit and tacit knowledge and also plays distinct roles on the individuals' sharing behavior in work team context. The results also demonstrate that an optimal social network configuration maximizes team members' knowledge sharing. Our investigation from a multilevel approach articulates how social capital at different levels in conjunction influences individual sharing behavior, contributing to the existing social capital and social network theories as well as the literature of knowledge management.