Alcohol use represents a global health problem, especially for Latin American youth. As part of the Global Smart Drinking Goals campaign, a family-based preventive intervention was adapted and piloted in Mexico based on an existing evidence-based program, Guiding Good Choices. In this study, we explored the malleability and session-specific mean-level changes in protective and risk factors targeted by the adapted family intervention as related to the prevention of underage alcohol use and abuse. The sample consisted of 177 parents working at four private local companies who had children between the ages of 8 and 16. Data were collected before and after each program session. Linear mixed-effects models were used to examine growth trajectories and session-specific mean differences for selected etiologic factors. Significant effects on protective and risk factors were found. Among protective factors, positive family involvement showed the most considerable linear growth over time, while clear standards for youth showed the largest within-session increase. The greatest linear decrease in risk was observed for family conflict, which also showed the greatest pre-, and post-session reduction. Our findings suggest that the adapted program helped families develop protection against, and reduce risk of, alcohol use in their adolescent children. Results from this exploratory pilot study provide support for further rigorous evaluation and dissemination of the adapted intervention for Hispanic families.