Drawing from an ecodevelopmental framework, this article examines if adding a parenting component, Families Preparing the New Generation (Familias Preparando la Nueva Generación), to an efficacious classroom‐based drug abuse prevention intervention, keepin'it REAL, will boost the effects of the youth intervention in preventing substance use for middle school Mexican‐heritage students. Youth attending schools in a large urban area in the Southwestern U.S. (N = 462) were randomly assigned to 1 of 3 conditions: parent and youth, youth only, or control. Using ordinary least squares regression, changes in youth substance use outcomes were examined. Results indicate that youth whose parents also participated in prevention programming exhibited significantly lower use of alcohol, cigarettes, marijuana, and inhalants compared to youth who received only keepin'it REAL. These initial effects indicate that involving parents in prevention efforts can strengthen the overall efficacy of a youth prevention intervention. This article discusses specific implications for the design of prevention interventions, policy, and future research.