Video game developments allow players to design their own personalized avatars. Previous research has shown that this capability increases levels of aggression within socially acceptable forms of violence. Using the general aggression model (GAM), the current study examined the effect of avatar personalization on behavioral aggression within a violent video game. Participants who played a violent video game and designed their own avatars were significantly more aggressive than those who played the same violent video game with a generic avatar, and were also more aggressive than those who played the nonviolent video game, regardless of whether or not they designed their own personalized characters. Limitations and directions for future research are discussed.