Mental retardation is a disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in adaptive behaviors. Children with mental retardation learn more slowly than a typical child and may take longer to learn language, develop social skills, and take care of their personal needs, such as dressing or eating. It was hypothesized that mentally retarded pupils would be socially maladjusted and would stigmatize misfits. It was also hypothesized that girls and boys would be different in this respect. Fifty mental retarded pupils (girls and boys with slight degree of impairment) completed the modified peer maladjustment subscale. Results of statistical analyses showed that mentally retarded pupils had moderate levels of peer maladjustment and boys more often stigmatized misfits than girls. Moreover, the degrees of peer maladjustment correlated with stigmatization, but only in the group of females. These results were discussed in the light of hypotheses.