Conducted a meta-analytic evaluation of the effectiveness of school-based child abuse prevention programs. Literature searches identified 27 studies meeting inclusion criteria for use in this meta-analysis. The average effect size for all programs studied was 1.07, indicating that children who participated in prevention programs performed 1.07 SD higher than control group children on the outcome measures used in the studies. Analysis of moderator variables revealed significant effects for age, number of sessions, participant involvement, type of outcome measure, and use of behavioral skills training. Most important, programs presented over 4 or more sessions that allowed children to become physically involved produced the highest effect sizes. Although most often used only with younger children, findings suggest that active, long-term programs may be more effective for children of all ages.