The effects of individual and group performance on children's evaluations of themselves and in- and out-group were examined. 128 girls and boys aged 3, 5, 7, and 9 years were randomly assigned to alleged "fast" or "slow" teams and asked to make various self, interpersonal, and intergroup evaluations. These showed strong developmental changes. Intergroup comparisons were made as early as 3 years, and this age group was sensitive to the relative standing of their team. However, the 5-year-old children showed markedly high self-evaluations, very strong in group bias in their evaluations of the 2 teams, and a high level of group cohesion irrespective of their own team's alleged performance. Gender differences were observed in self-evaluations after team assignment (boys responding more than girls to their team's alleged performance). The implications of these findings for recent work based on cognitive-developmental and social identity theories are discussed.