This chapter focuses on the link between playing violent video games and exhibiting aggressive behavior. Experimental and correlational studies have reported that playing violent video games is associated with increased levels of physiological arousal, decreased prosocial behaviors, greater hostility, more frequent arguments with teachers and poorer school performance, and more frequent physical fights and aggressive or antisocial behavior. Numerous video games contain some degree of violence, frequently with the player's character as both protagonist and perpetrator of the violence. In the virtual world of violent video games, the player may kill or injure computer-generated characters or other online gamers without any consequence, including punishment. Parental involvement is particularly important to ensure that children and adolescents with high levels of anger and hostility, conduct disorder, or antisocial behavior have restricted or no access to violent video games and other violent media.