Gender differences in self-concept among children and adolescents continues to be a topic that generates substantial interest in the professional literature as well as the popular press. In fact, notions of particular patterns of gender differences in self-concept have often been accepted without critical questioning, despite frequent flaws in the methodology used to identify such findings. Additionally, important changes in theory development regarding self-concept have occurred during the past two decades, raising questions regarding some of the assumptions on gender differences that resulted from older, unidimensional models of self-concept. The purpose of this investigation was to consolidate the recent and more sophisticated research on gender differences in self-concept among children and youth. This was done by conducting a systematic meta-analysis of research published since 1980, particularly involving self-concept as a multidimensional phenomenon. Through a comprehensive search process, 22 studies representing over 19,000 child and adolescent participants were ultimately analyzed. Mean effect size estimates across dimensions showed a complex pattern of gender differences and similarities, some of which were consistent across grade levels and others of which were not. Although some of the findings defied stereotypes, several were consistent with previous notions regarding differences in self-concept based on gender. The direction and complexity of these results emphasizes the importance of discussing developmental differences in self-concept in a thoughtful and careful manner and argues against the use of simplistic global generalizations. Limitations of the present investigation, as well as recommended directions for future research, are discussed.