The present study investigated changes in self-esteem, academic self-concept, intellectual self-concept, and social self-concepts of acceptance, assertion, relations with same-sex peers and relations with other-sex peers with 177 gifted students participating in a 16-day summer school in Germany. Students were assessed three times by self-report questionnaires, one or three weeks before the school started, at the seventh day, and at the fifteenth day of the summer school. Scales showed strict measurement invariance over time such that scale means could be compared by repeated measures ANOVAs. Although academic self-concept did not change over time, intellectual self-concept showed a decrease during the visit of the school that was of small effect size (Hedges' g = 0.13). Descriptively, self-esteem showed a positive development over time, but this increase was small and not significant. The social self-concepts of acceptance, relations with same-sex peers, and relations with other-sex peers significantly increased over time (Hedges' |g| between 0.14 and 0.40). Changes were comparable for male and female students. Overall, our findings support summer schools as an effective means to foster gifted students' socioemotional needs.