This meta-analysis was designed to examine the effectiveness of school-based mental health interventions. After refining search criteria, 1138 articles were returned from ERIC, EBESCO, and Psychological Behavior Science Collection. Next, article abstracts, and full text were screened to ensure each article met the study criteria before articles were coded. After coding, the researcher conducted meta-analysis and meta-regression which examined the relationship between school-based mental health interventions and moderators (e.g., study, intervention, and outcome measure characteristics). The results of the meta-analysis show that school-based mental health interventions are effective. Key findings of the meta-regression reveal program length does not influence the effectiveness of an intervention, social-emotional learning interventions are the most effective, and school-based mental health interventions are more effective at the secondary level than the primary level. Therefore, implications for practice are that decision makers should be intentional about incorporating school-based mental health interventions into their school community. Policy makers must also consider reforming systems that evaluate student success to prioritize student health. Finally, future research should focus on examining the effectiveness of school-based mental health interventions for BIPOC populations and across school settings such as rural and urban schools, as well as examine effectiveness of program/intervention intensity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]