Effectiveness of School-Based Interventions on Adolescents’ Subjective Well-Being: A Systematic Review and Meta-Analysis of Recent Evidence

Abstract Adolescent mental health and well-being have become key priorities in educational and public health agendas, accompanied by a rapid expansion of school-based programs in recent years. This systematic review and meta-analysis aimed to evaluate the effectiveness of school-based interventions (SBIs) in promoting adolescents’ subjective well-being (SWB) and to explore potential sources of heterogeneity. A systematic search was conducted in PubMed, PsycInfo, Scopus, Web of Science, and ERIC for studies published between 2020 and 2025, a period marked by intensified implementation of well-being programs and methodological innovation in the field. Eligible studies included randomized controlled trials and quasi-experimental designs delivered to adolescents aged 10–19 years in school settings. Methodological quality was assessed using Risk of Bias 2 (RoB 2) and ROBINS-I tools, and a random-effects model was applied using Comprehensive Meta-Analysis software. Thirteen studies were included, comprising 3,011 participants. The pooled standardized mean difference indicated a small but statistically significant positive effect (SMD = 0.32, 95% CI [0.13, 0.51], p < 0.01), with substantial heterogeneity (I² = 84.8%). Subgroup analysis by participants’ mean age revealed no statistically significant differences between age groups, suggesting that contextual and implementation factors may account for the variability in outcomes. Interventions based on social-emotional learning, positive psychology, mindfulness, compassion-based approaches, and structured physical activity showed benefits for well-being-related outcomes. Although the diversity of measures, short follow-up periods, and concentration of studies in high-income countries limit generalizability, the results support the feasibility and relevance of integrating evidence-based well-being programs into educational systems as part of comprehensive adolescent mental health promotion strategies.