This research establishes a group model of social support, in which the entitativity of the group mediates the effectiveness of the group in improving well-being. In order to test this model, Experiment 1 established the role of group membership in experiencing negative feedback. Groups, particularly highly entitative groups, respond to negative feedback with higher levels of anger and lower levels of anxiety and other negative emotions. Experiment 2 replicated the same emotional pattern by analyzing sororities' (highly entitative) and dorm groups' (less entitative) responses to possible outcomes of an important competition. Experiment 3 examined the role of varied individual and group feedback. Highly entitative groups responded more strongly to group feedback and responded less negatively to negative individual feedback. Taken together, these studies suggest that entitativity may be an important mechanism in explaining the positive impact of group social support.