A key contributing factor to the initiation and escalation of substance use during early adolescence is affiliation with deviant peers. These affiliations often arise when socially isolated and rejected youth aggregate and reinforce substance use and other deviant activity within the group (i.e., "deviant peer clustering"). Even though the field has developed a number of efficacious prevention programs, few have demonstrated strong effects on deviant peer clustering. Further, on a national level, substance use among adolescents continues to be high, suggesting that a fresh approach to prevention with a renewed focus on the peer context is needed to create a broad, sustainable public health impact.