This paper describes a model that explores the critical roles of three group composition factors (social category diversity, value diversity, and informational diversity) and two moderating variables (task type and task interdependence) on work group performance and morale. The three types of diversity are proposed to exhibit both main effects and interaction effects (interacting both with each other and with task type and task interdependence) on work group performance and morale. Relationship and task conflict are proposed to mediate many of these effects. Empirical evidence for these relationships and their implications for those wishing to manage a diverse workforce are discussed.