Gardner et al. compared sport participants with youth who participate in other organized activities, but not sport, and with youth who do not participate in any organized activities. The authors examined the peer processes that might explain the relations and how this may vary as a function of youth’s prior risks for delinquency and gender. In addition, Gardner et al. examined both violent and nonviolent delinquency. Significant findings were obtained for boys, though not girls, for nonviolent offending only and only for the amount of time boys spent in unstructured social situations; peer deviance only mediated the association between sports and nonviolent delinquency among boys with higher scores on prior externalizing problems.