There is a consensus among educators, parents, and policymakers that education should include a focus on supporting essential social and emotional capacities to help children navigate the world successfully. To develop these competencies, many schools adopt social and emotional learning (SEL) programs. The report on which this brief is based reviews the findings from 12 meta-analyses of school-based SEL programs. Across these studies, there is a consistent, reliable effect of tested, evidence-based SEL programs on students' social, emotional, behavioral, and academic outcomes in PreK--12th grade, including the development of social and emotional skills, improved academic engagement and performance, growth of positive social behaviors, and lower rates of behavior problems and psychological distress. These findings are applicable across gender, ethnicity and race, income, and other demographic variables. [This study was supported by the Whole Child Policy Table, an LPI project funded by the Carnegie Corporation of New York, Chan Zuckerberg Initiative, William and Flora Hewlett Foundation, Harmony and Inspire at National University, Pure Edge, Inc., and the Wallace Foundation. For the full report, see ED630374.]