A review and meta-analysis of 42 group and single-case studies evaluating antecedent exercise (AE) as a means of reducing disruptive behaviors was conducted. Of 16 group studies, 12 produced positive results and 4 produced negative results. The weighted mean effect sire, expressed as Cohen's d, was .33 with a standard error of .08. Moderator analysis indicated that studies using direct behavioral observation, hyperactive subjects, or nonaerobic exercise obtained greater effects, and that studies of higher quality obtained weaker effects. Of 26 single-case studies, 22 produced positive results, 1 produced no effect, and 3 produced negative results. The weighted mean effect size, expressed as d, was 1.99 with a standard error of .411. Among the single-subject studies, moderator analyses were unable to detect statistically significant moderators of effect sire. Information was reviewed suggesting that AE is socially acceptable, can be implemented with treatment integrity, and has a benign side effect profile. The extent to which AE is functionally based remains open to question due to a lack of understanding regarding mechanism of action. Ten hypothesized mechanisms of action are briefly discussed.