The present study evaluated the effectiveness of school-based prevention and intervention programs for children and adolescents at-risk for and with emotional disturbance. Published outcome studies (k = 29) from December, 1988, to March, 2006, including 1405 children and adolescents were reviewed. Each investigation was coded on several variables describing the child, parent, and teacher samples, as well as reported outcome results. The overall mean weighted effect size was 1.00 at post-test and 1.35 at follow-up. Mean weighted ESs were 0.42 for between-subjects design studies, 0.87 for within-subjects design studies, and 1.87 for single-subject design studies. Prevention programs yielded a mean weighted ES of 0.54 and intervention programs produced a mean weighted ES of 1.35. Findings for specific outcome foci are presented and implications are discussed. (Contains 1 figure and 3 tables.)