The purpose of this study was to investigate reliability of the Social Skills Rating Systems of Gresham and Elliott for use in Iran. The sample consisted of 304 students aged 6 to 12 years, selected from the elementary schools in Shiraz, Iran. Parents' and teachers' ratings of social skills and behavioural problems and self-rating of social skills were applied in this study. Pearson correlations between parents' and teachers' ratings were low to moderate. Correlations between social skills subdomains and behavioural problems subdomains were low to high. Cronbach coefficients alpha were satisfactory for the two subdomains.