The purpose of this study was to examine the social validity of the Social Skills Improvement System-Classwide Intervention Program (SSIS-CIP) for teachers in the primary grades. Participants included 45 first and second grade teachers who completed a 16-item social validity questionnaire during each year of the SSIS-CIP efficacy trial. Findings indicated that teachers generally perceived the SSIS-CIP as a socially valid and feasible intervention for primary grades; however, teachers' ratings regarding ease of implementation and relevance and sequence demonstrated differences across grade levels in the second year of implementation. [This article was published in "School Psychology Quarterly," (EJ1153009).]