The proposed meta-analysis of 61 independent samples aims to identify whether, and if so under what conditions, team working in organizations is related to organizational effectiveness. Team working had a significant though small positive relationship with both performance outcomes and staff attitudes. Our contingency analyses further showed that team working had a stronger relationship with performance outcomes if accompanied by complementary HR measures and in non-health-care settings. Finally, we found that team working is more strongly related to attitudinal outcomes in Sociotechnical Systems and health-care settings.