We analyzed the relations between teacher reports of aggressive behaviors, caregiver reports of their use of physical discipline, anger perception accuracy, and anger perception bias in middle childhood and teacher reports of aggressive behaviors two years later in a sample of children from economically disadvantaged families (n = 152). Fisher r-to-z analyses showed a gender difference in the relation between anger perception accuracy and aggressive behavior in third grade. For girls, anger perception accuracy was significantly negatively related to aggression, and for boys, there was no relation between anger perception accuracy and aggression. Hierarchical multiple regression analyses showed that third grade aggressive behavior, caregivers' reports of their use of physical discipline, and anger perception bias were significantly positively related to teacher reports of aggressive behavior two years later after controlling for gender and anger perception accuracy.