Individuals with ADHD are at markedly high risk for increased substance use and Substance Use Disorder (SUD). Given the strong evidence for the negative trajectory of individuals with co-occurring ADHD and substance use initiation, the goal of this study is to conduct a controlled examination of a brief, early intervention (BEI) for substance modified for adolescents with ADHD. Importantly, this intervention will address individuals who are at risk for problems with substance use, but do not yet meet criteria for severe SUD.