This chapter gives a comprehensive state-of-the-art review on the effects that exposure to or enactment of violence in mainstream media has on aggressive behavior, emotions, and empathy. In line with contemporary technological developments, the authors also cover the more and more widespread consumption of violent video games, which put the player in a more active role than traditional media (such as television) put their viewers. As the field is extremely controversial, the authors are careful in their analysis of the actually existing evidence as well as in their conclusions and recommendations for future research. Despite all controversy, and after reviewing existing literature, as well as a large number of own empirical work, the authors come to the conclusion that there is evidence for increased aggressive motivation and impulsivity as a result of exposure to media violence, but that it is not clear yet how much it affects people’s real-life behavior. Nevertheless, it is clear that there is no evidence for cathartic effects, a conclusion that is similar in research on the effects of filmed violence, and an idea that had been present in the controversy for decades but can now be abandoned.