Empirical research on the effects of school sport policies on children's physical activity is limited. This study examined sport policies (intramural vs. varsity), physical settings within schools, and supervision in relation to physical activity using the System for Observing Play and Leisure in Youth (SOPLAY). Data were collected on physical activity levels of children in four middle schools. Regression analyses assessed the main effects of sport policy, type of physical activity setting, and supervision as well as interactions. Regression models were stratified by gender. Children in intramural schools were more likely to use indoor spaces and be boys. Regression models indicated that varsity sport programs were associated with lower physical activity levels among boys but not girls. Significant associations between type of physical activity settings and physical activity levels were observed only for boys. Adult supervision was not associated with children's physical activity levels. Finally, descriptive results showed athletic facilities were under-utilized in all schools.