This study examines a cross-sectional structural equation model of participation in youth activities, neighborhood adult support, individual decision making skills, and delinquent behavior in urban middle school youths (n = 2611). Results indicate extracurricular activity participation had both direct and indirect associations with delinquent behavior. Breadth, but not intensity, of activity participation had a positive association with neighborhood adult support and higher levels of adult support were associated with higher levels of youth decision making skills. Higher levels of decision making skills were, in turn, associated with lower levels of delinquent behavior. A direct positive association between intensity of activity participation and delinquent behavior was noted, after accounting for other effects in the model. The specificity model revealed that this association was mostly due to participation in neighborhood clubs (as opposed to sports, school clubs, church, helping/volunteer, or music, art, or drama). Implications and limitations of the study are discussed. (Contains 5 tables and 2 figures.)