This study takes a situational approach to testing criminogenic peer influence effects on substance use by examining audience characteristics at the last two parties that adolescents attended. We examine the applicability of situational approaches to social learning theory and symbolic interactionist perspectives on criminogenic peer group effects.We found that higher levels of substance use are more likely to occur in smaller group settings. But having more friends use alcohol/cannabis and in larger amounts is strongly related to greater personal substance use. Further, it was found that increases in the amount that friends drink/smoke from one party to the next is related to increases in personal substance use.