Social adjustment is critical to educational and occupational attainment. Yet little research has considered how the school's socioeconomic context is associated with social adjustment. In a longitudinal sample of Australian 4- to 8-year-olds (N = 9369; 51% boys) we tested the association between school average socioeconomic status and social skills (parent and teacher reported). Models controlled for age 4 social adjustment and additional covariates. Results showed that children from more advantaged schools are more likely to have better prosocial behavior and fewer peer and conduct problems. An interaction between family and school average socioeconomic status (SES) suggested that this association was mainly present for children from lower SES backgrounds.