Background and aim School violence and aggression have become an increasing concern to public health professionals, clinicians, policy makers, educators, and the general public. It is a multidimensional problem with biological, psychological, social, and environmental roots. The purpose of this study was to assess the prevalence of aggressive behavior and to explore the associated psychosocial risk factors among preparatory school children. Patients and methods A multistage stratified sample of 380 students of both sexes, 12–15 years old, was collected from the preparatory schools at Tanta City through the academic year 2016–2017. Aggressive behavior was assessed by Modified Overt Aggression Scale. Arabic version of Kiddie Schedule for Affective Disorders and Schizophrenia − Present and Lifetime Version was applied to assess current and past episodes of psychopathology in children and adolescents who had high scores of aggression. Results Overall, 23.7% of the studied sample had aggression, and it was distributed as follows: 0.8% of the sample scored high on aggression scale, 5.5% moderate, 7.4% mild, and 10% minimal. Risk factors of aggressive behavior included male sex; second child of the family; smoking; drug addiction; watching action movies; history of physical abuse; no hobbies or playing sports; widowed or divorced parent; poor relationships with parents, friends, and teachers; living in extended families; family history of psychiatric illness; low socioeconomic class; a drug-addict family member; physical abuse in the family; unfavorable school atmosphere; and history of dropping class. Overall, 8.9% of aggressive students had attention-deficit hyperactivity disorder, 6.7% had conduct disorder, 6.7% had depression, 3.3% had oppositional defiant disorder, and 1.1% had substance use disorder. Conclusion School aggression and violence is a frequent and a multifaceted problem among the school adolescents.