While martial arts are becoming more and more popular in American society, very little research is done on what relationship these practices have with violence. Previous research has shown a link with Eastern martial arts and reducing levels of aggression. Meanwhile, much of the limited social theory on violence contends that modern, Western culture reduces aggression by way of placing more emphasis on self-control. This paper set out to test these contradictory ideas by comparing aggression levels and emphasis placed on self-control between different styles of Eastern and Western martial arts. The findings did not support either of these ideas. Neither emphasis on self-control nor style of martial art had a significant negative effect on levels of aggression. However, the findings were consistent with Randall Collins’ micro-sociological theory of violence.