Today's organizations have to deal with complex challenges to pursue their ultimate goals of viability and sustained competitive advantage in the world of industry (Boxall & Purcell, 2003). These global challenges and competition cause pressures that are influencing the emergence of teams as a basic building block of organizations (Kozlowski & Bell, 2003). In developing a conceptual model on the relationship between expertise diversity and team performance, I argue that different levels of expertise diversity may facilitate distinct types of team learning and team performance dependent upon type of team task. By differentiating between adaptive team learning, generative team learning, and transformative team learning, I attempt to clarify how team learning as a mediator can link the different levels of expertise diversity to the distinct team performance dimensions of effectiveness, efficiency, innovation and transformation. Moreover, type of team task moderates the relationships between expertise diversity, team learning, and team performance.