Despite decades of concern about disparities in educational outcomes for low SES students and students of color, there has been limited rigorous study of programmatic approaches for reducing these disparities in elementary or middle schools. We conducted integrative data analysis (IDA) of the combined data from eight Institute of Education Sciences funded cluster randomized trials to address the research gaps on social and behavioral outcome disparities. The final analytic sample includes 90,880 students in varying grade levels from kindergarten to grade 8 in 387 schools in 4 states (Maryland, Missouri, Virginia, and Texas). Two-level hierarchical linear modeling was used for multilevel moderation analysis. This study provided empirical evidence that there were significant gender, racial, and socioeconomic disparities on social and behavioral outcome measures for elementary and middle school students, the disparities significantly varied across schools, and the disparities could be reduced by interventions. We discussed our findings, implications for interpreting effect sizes of interventions using disparities as empirical benchmarks, and study limitations. We concluded with suggestions for future research. [For the corresponding grantee submission, see ED622033.]