Abstract

Despite increasing interest in promoting well-being among children and adolescents, few evidence-based interventions have been evaluated, particularly in Latin America. This study assessed the effectiveness of PromoBIENdo, a multidimensional and multicomponent school-based program designed to promote well-being, in early adolescents (6th and 7th grade) using a quasi-experimental design. One hundred and twenty-three 6th and 7th-grade students participated, with 67 in the experimental group. No statistically significant differences were found between groups in age or sex before the intervention. The experimental group engaged in all four modules of the program over 12 consecutive weeks. Post-intervention results indicated that students in the experimental group showed statistically significantly higher levels of overall subjective well-being, as well as greater satisfaction with school, peers, and themselves, both in pre-post measures and compared to the control group. Additionally, the experimental group did not exhibit the typical developmental decline in well-being observed in the control group. Effect sizes ranged from small to large (e.g., ?2? = 0.171 for school satisfaction), indicating meaningful impacts of the program. These findings provide preliminary evidence supporting the effectiveness of PromoBIENdo in promoting subjective well-being in children and underscore the relevance of implementing universal, evidence-based interventions in school settings to support mental health. Impact Statement This study provides initial evidence that a school-based, multidimensional well-being program can effectively improve students’ satisfaction with school, peers, and themselves. The findings highlight the importance of integrating mental health promotion into school daily activities, especially in socially vulnerable contexts. © 2025 National Association of School Psychologists.