Youth violence is violence or aggression perpetuated by or targeted against youth and includes many forms such as violent crime, physical violence (e.g., fighting, use of firearms), and the numerous manifestations of bullying (e.g., overt, social/relational, and cyber bullying). New research is needed to enhance our understanding of the factors and processes associated with youth violence. This research focuses on key factors within individuals and multiple contexts that may robustly predict the perpetration and amelioration of violence among youth but that have received scant attention in previous research, especially in concert with each other. Specifically, the factors within individuals the investigators examined include cognition (e.g., attitudes towards retaliation and bystander intervention) and social-emotional adjustment (e.g., rejection sensitivity, affect, aggressive behavior and victimization) while the multiple contexts will include peer (e.g., characteristics and status of peer group, sociometric and perceived popularity), school (e.g., school connectedness, student-teacher relationship), and family contexts (e.g., attachment, family hostility). This dataset seeks to aid scholars hoping to understand adolescents' attitudes and judgments surrounding peer aggression, with attention both to attitudes surrounding bystander intervention to stop aggression and retaliation when exposed to such aggression. This project is a year-long longitudinal study with 6th graders and 9th graders in order to identify factors related to responses to peer aggression and to examine these relations over time.