The "Social Skills Improvement System" (SSIS; Gresham & Elliot, 2008) is designed to assist in the screening and classification of students (ages 8 to 18) who are suspected of having significant social skills deficits, and to offer support in the development of interventions for those found to display significant social skills impairments. Although the SSIS is a revision of the widely-used "Social Skills Rating System" (SSRS; Gresham & Elliott, 1990), the strengths of the SSRS are retained in the SSIS. Improvements include updated norms, four additional subscales, greater overlap across forms, validity scales, improved psychometric properties, Spanish versions of forms, and direct links to intervention. This article reviews the SSIS "Rating Scales" (SSIS-RS), a component of the SSIS. In addition to the SSIS-RS, the SSIS includes the "Performance Screening Guide" (intended for universal assessment [Tier 1]; Elliot & Gresham, 2007a), the "Classwide Intervention Program Teacher's Guide" (Elliot & Gresham, 2007b), and the "Intervention Guide" (Elliott & Gresham, 2009).