Objective: To assess the impact of a parenting intervention, Familias: Preparando la Nueva Generación (FPNG), intended to support children, on parents heavy drinking. We hypothesized that parent participants of FPNG would reduce their heavy drinking at 1-year follow-up. Methods: Parents (N = 281) of middle school children from a large, low-income metropolitan area in the Southwest United States participated in a randomized control trial over 2 years. Results: A logistic regression analysis using the maximum likelihood test determined that at Wave 3, parents receiving FPNG reduced heavy drinking behaviors compared to parents in the youth-only condition (odds ratio = .86, p < .05). Conclusions: Participating in the parenting program can effectively curb heavy drinking behaviors in parents—an important mechanism through which one may expect changes in youth risk behavior. The practice, policy, and research implications of these unintended findings are promising to the overall effectiveness of a parenting intervention for Mexican-heritage families.