The purpose of this study is to examine the effects of violent behavior on self-esteem among high school students. The research was conducted with 447 male students at two vocational high schools from December 3, 2008 to March 23, 2009. The analysis was performed using SPSS 12.0 Version and the statistic significance was set at p<0.05. The results are as follows: As for correlation between violent behavior and self-esteem, there was correlation with peer relation satisfaction alone (r=-0.198, p<0.01). As for the effects of violent behavior on self-esteem, only peer relation satisfaction (b=-0.188, t=-3.803, p<0.001) and bullying (b=-0.0130, t=-2.062, p<0.05) significantly affected self-esteem. To improve self-esteem among vocational high school boys, it is necessary to activate systematic education programs in pursuit of satisfaction with peer relations and school life.