The purpose of this study is to examine the influencing factors on bystanders role in school violence on the premise that not only the role of aggressor and victim who are directly involved in school violence but the role of bystander is important as well. To this end, this study collected data from 760 male․ female adolescents who are enrolled in 4 middle schools and 4 high schools located in Daegu Metropolitan City, and used data of 721 students excluding unreliable response in final analysis. The findings showed that according to the result of investigating the influencing factors on bystanders role in school violence of adolescents by classifying into the roles of bystander, defender, and follower, the influencing factors on bystanders role were gender, level of school, empathy for victims, permissive attitude for violence, rearing attitude of parents, peer support, and school atmosphere. For influence of major variables on the role of defender, it was identified that gender, empathy for victims, peer support, and school atmosphere make effect. Lastly, influencing factors on follower’s role were sexual, sympathy for victims, permissive attitude for violence, rearing attitude of parents, and school atmosphere.