Children and adolescents (N= 1,057), divided by gender, at fourth, seventh, and tenth grades, from two mid–sized cities in the United States and in Japan, were surveyed regarding their evaluations of peer group exclusion of atypical peers. Six reasons for atypicality were being aggressive, having an unconventional appearance, acting like a clown, demonstrating cross–gender behavior, being a slow runner, and having a sad personality. Analyses revealed significant effects for age, gender, country membership, and the context of exclusion. With age, children demonstrated context sensitivity, and believed that the excluded child should not change him– or herself to be accepted by the group. Across contexts, girls were less willing to exclude than were boys, and were more tolerant of differences. The context of exclusion had an effect on all forms of judgments about exclusion, and there were very few overall effects for culture. Most children disagreed with the decision to exclude, believed that they were different from the atypical child, and believed that the excluded child should change him– or herself to be accepted by the group. The results support a theory of developmental social cognition in which multiple sources of influence have a significant effect on social decision making involving the exclusion of others.