Adolescent participation in structured activities, meaning those with adult leaders, regular meetings, and skill-building activities, is related to good adjustment. Participation in unstructured, unsupervised, peer-oriented activities is related to poor adjustment. Structured activity participation is high in early adolescence and then declines, raising the question of why youths leave structured activities. The authors examined explanations involving parents and peers. They used longitudinal data from 861 youths (ages 13-17 years). Results showed that, compared with youths who stayed in structured activities, those who switched to hanging out on the streets were less likely to have peers in structured activities and had less positive feelings about the home context and more negative interactions with parents. In addition, delinquency predicted switching to hanging out in the streets and never joining structured activities in the first place. The results concerning parents support a theoretical explanation of how parents might unintentionally affect youths' leisure choices. Furthermore, the authors found some indications that positive feelings at home might protect youths who switch from structured activities to hanging out on the streets from increases in delinquency.