Longitudinal data from kindergarten to 5th grade on both family involvement in school and children's literacy performance were examined for an ethnically diverse, low-income sample (N = 281). Within families, increased school involvement predicted improved child literacy. In addition, although there was an achievement gap in average literacy performance between children of more and less educated mothers if family involvement levels were low, this gap was nonexistent if family involvement levels were high. These results add to existing evidence on the value of family involvement in school by demonstrating that increased involvement between kindergarten and 5th grade is associated with increased literacy performance and that high levels of school involvement may have added reward for low-income children with the added risk of low parent education. As such, these results support arguments that family involvement in school should be a central aim of practice and policy solutions to the achievement gap between lower and higher income children.