The successful management of diversity at work is currently the most important and challenging issue for managers in organizations. While scholars have deepened the understanding of the nature of diversity by proposing new concepts such as “team faultline,” previous studies on diversity focused more on the structural aspect of diversity, disregarding the role of the psychological aspect of diversity among team members. To overcome the above limitations, this study develops an integrative model of the effects of team faultlines, value diversity, and task design on team process and effectiveness. Drawing on the categorization-elaboration model, we suggest that team faultlines have a positive effect on team performance through team mental model only when both team value diversity and team task design are high. This paper intends to contribute to the literature of team diversity, team design, and team mental model.