The purpose of the current investigation was to examine the associations between a variety of measures of extracurricular participation and indicators of youth development. We use data from the Childhood and Beyond Study, a larger longitudinal study of adolescent development. The sample is primarily White middle-class adolescents in Grades 7 through 12. First, we examined the relation between the duration of involvement in school clubs and in organized sports over a 3-year span and youth development. Second, the linear and nonlinear relations between the number of extracurricular activities and youth development 1 year later were examined. Finally, we tested the link between the breadth of participation and youth development 1 year later. In general, across all 3 sets of analyses, our findings indicate that greater involvement in extracurricular activities is associated with academic adjustment, psychological competencies, and a positive peer context. The results were strongest for the oldest group of youth.