Background: Physical aggression is a hostile form of aggression. It aims to cause bodily damage. It includes kicking, molesting, harassing, biting, pushing, torturing, fighting, and bullying. There is limited study in Ethiopia. Therefore; studies are needed for physical aggressive behavior which varies among high school students. Objective: The study aimed to assess the prevalence and factors associated with physical aggressive behavior among high school students at Bahir Dar city, Ethiopia Methods: Institutional based cross-sectional study was employed from June 18 to July 16/ 2022 at Bahir Dar city high school regular students. A multistage random sampling technique was used. Physical Aggressive behavior was assessed by a direct and indirect aggression scale among 566 high school students. The collected data were checked for completeness and consistency; and then coded. The data were entered into Epi data and exported to Statistical Package for Social Science. Finally, binary logistics regression has been used to identify the factors that affect physical aggressive behavior. Results: The prevalence of physical aggressive behavior was found to be 18.4% (95%CI 15.3, 21.8).Being male (AOR=2.72 95%CI 1.63,4.56),small family size of parents (AOR=2.84;95%CI1.35,5.95),family history of mental illness(AOR=2.73;95%CI 1.48,5.04),history of medical illness(AOR=4.05;95%CI 2.43,6.77),and a history of being abused (AOR=2.73 95%CI 1.73, 4.30) were positively associated with physical aggressive behavior. Conclusion: Nearly one fifth of students were found to have physical aggressive behavior in Bahir Dar city .Sex, family size of parents, medical illness, history of being abuse, and family history of mental illness were significantly associated with physical aggressive behavior. This suggested that school counselor regarding to physical aggressive behavior should emphasize on male students, small family size, and family history of mental illness, medical illness and being abused to institute routine mental health screening services and implement appropriate interventions. Keyword: physical Aggressive Behavior, high school students, Ethiopia