Youth violence is recognized as a major public health problem in the United States and the world. Over the past ten years, progress has been made in documenting the factors that contribute to violent behavior. Emerging research is deepening our understanding of the individual and societal influences that contribute to and protect against youth violence. However, much work still remains to be done in this field, both in examining potential causes and in designing effective intervention strategies. This chapter highlights specific dimensions of youth violence prevention selected by the authors because these dimensions are the focus of public attention, are emerging as critical issues in the study of youth violence, or have a unique place in the current political and social context. We focus on the developmental pathways to violence, factors that mediate and moderate youth violence, the role of culture and media in youth violence, school-based violence such as school shootings and bullying, and the training of health care professionals.