A meta-analysis of 19 studies (N = 15,992 offenders) showed a significant inverse relation between more mature moral development and recidivism. Moderator analyses revealed a larger effect size for moral cognition (r = .20) than for moral emotion (r = .11). Effect sizes for production measures (r = .57) were much larger than for recognition measures (r = .16) and unstructured (clinical) judgment (r = .10). Larger effect sizes were found for female delinquents (r = .32) than for male delinquents (r = .21). Only small differences in effect sizes were found between juvenile delinquents (r = .10) and adult delinquents (r = .16). Finally, self-report measures of recidivism revealed much larger effect sizes (r = .32) than official reports of recidivism (r = .09). The discussion focuses on the theoretical and practical meaning of the magnitude of the effect size for the relation between moral development and recidivism.