The Social Skills Improvement System-Rating Scales (SSIS-RS) is a multi-informant instrument assessing social skills and problem behavior in children and adolescents. It is a revised version of the Social Skills Rating System (SSRS). A Norwegian translation of the SSRS has been validated, but this has not yet been done for the Norwegian translation of the SSIS-RS. This study compared the Norwegian versions of the SSRS and the SSIS-RS administered to samples of children (aged 8-12 and 13-16 years) and their parents and teachers (n = 599). The results indicated moderate to strong relations between the common subscales across all forms of the two instruments and acceptable to excellent internal consistency across all common subscales. We conclude that the SSIS-RS is a good instrument for measuring social skills and problem behavior among children and adolescents in Norway.