"Social skills training" is not a specific curriculum, but rather a collection of practices that use a behavioral approach for teaching preschool children age-appropriate social skills and competencies, including communication, problem solving, decision making, self-management, and peer relations. "Social skills training" can occur in both regular and special education classrooms. The What Works Clearinghouse (WWC) identified three studies of "social skills training" that both fall within the scope of the Early Childhood Education Interventions for Children with Disabilities topic area and meet WWC evidence standards. All three of these studies meet standards without reservations and together, they included 135 children with disabilities in early education settings in the United States. Although this report presents information about all three studies and their findings, the WWC's summary ratings of the evidence of effectiveness of the intervention are based on only two of the studies, that, together, included 103 children in their samples. The third study, which had a sample of 32 children, did not provide sufficient information to support calculation of effect sizes and statistical significance, which are used in determining the WWC's overall evidence ratings. The WWC considers the extent of evidence for "social skills training" on children with disabilities in early education settings to be small for two outcome domains--(a) cognition and (b) social-emotional development and behavior. "Social skills training" was found to have no discernible effects on cognition and positive effects on social-emotional development and behavior for children with disabilities in early education settings. Appended are: (1) Research details for Ferentino (1991); (2) Research details for Guglielmo and Tryon (2001); (3) Research details for LeBlanc and Matson (1995); (4) Outcome measures for each domain; (5) Findings included in the rating for the cognition domain; (6) Findings included in the rating for the social-emotional development and behavior domain; (7) Summary of subscale findings for the social-emotional development and behavior domain; (8) Summary of alternate contrasts for the cognition domain; and (9) Summary of alternate contrasts for the social-emotional development and behavior domain. A glossary is included. (Contains 7 tables and 12 endnotes.)