The current study evaluated the use of a manualized social skills program, Superheroes Social Skills, to increase the use of prosocial behaviors and decrease the use of aggressive behaviors for children with externalizing behaviors. The training was implemented by a school psychologist in a pullout group with four children with high-incidence disabilities and four typically developing peers at a public elementary school. The program implemented was a multimedia, high interest program that incorporates the use of animation to teach the lessons. This program also uses evidence-based practices (e.g., video-modeling, peer mediation, social stories, and self-management) to help increase the effectiveness of the intervention. There were eleven skills taught during one 30-minute session. Two sessions were taught per week. Children were videotaped during free play and recess observations for baseline, treatment, and follow-up. Their behaviors were then coded using a partial interval recording system. The behaviors observed were verbal aggression, physical aggression, neutral behavior, positive initiations, and positive responses. The observation codes were used to calculate effect sizes, percentage of nonoverlapping data points, and percentage of all nonoverlapping data points. The Social Skills Improvement System (SSIS) was used as a pre- and post-measure of treatment effectiveness. Measures were also used to determine social validity, consumer satisfaction, and treatment integrity. These measures were analyzed using descriptive statistics. Results indicated that this intervention was effective for decreasing aggressive behaviors, decreasing neutral play, and increasing positive responses in both the treatment setting and the generalized recess setting. Results were also maintained at a 2-week follow-up. Parents and participants indicated the program was effective and favorable. The results of the SSIS indicated minimal treatment effect, although teachers rated a significant increase in social skills. The treatment was implemented with high treatment fidelity. Overall, this study found that the Superheroes Social Skills Program was an effective intervention for children with high-incidence disabilities and externalizing behaviors. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]