This study examined the effectiveness of a social cognitive intervention program (SCIP) that was developed for aggressive children to address their social cognitive deficits and distortions related to all stages of Dodge’s 1994 model of social information processing. The randomized controlled trial study investigated the effectiveness of the SCIP based on Dodge’s model and compared the results with a social skill training (SST) and a waitlist (WL) control group. Study participants consisted of 97 aggressive boys, aged 9 to 13 years. The boys were referred for treatment to outpatient mental health clinics in various cities in the Netherlands. The results supported the effectiveness of both the SCIP and the SST. Although children in both treatment conditions improved, children in the SCIP condition showed improvement on more outcome measures at post-test and follow-up. The results support the expectation that focusing on deficits and distortions in SCIP instead of just focusing on SST would enhance treatment effectiveness because significantly greater improvement was found for the children treated with the SCIP. Tables and references