Objective: This research aimed at evaluating the moderator role of school connection on the impact of violent friends towards aggressive behaviors in adolescent students of Tehran high schools.

Methods: A sample of 3529 participants from Tehran high school students was selected using multistage sampling method. Participants completed school connection questionnaire (SCQ), Iranian adolescents risk-taking scale (IARS), and a demographic questionnaire. Data were analyzed by regression analysis.

Results: School connection affected male and female students differently. In males, school commitment and belongingness (two dimensions of school connection) reduced the impact of friends’ violent behaviors. However, regarding female students, school connection acts independently of friends’ violent behavior and has no effect on it.

Conclusion: Preventive programs should consider gender differences. In males, enhancing school commitment and belongingness might reduce tendency to violence in spite of the violent behavior of friends. However in females, effective disciplines in school or having nonviolent friends might reduce tendency toward violent behaviors.