Dissertation AbstractThere is persistent, nationwide concern about bullying in schools. Current conceptualizations of bullying primarily reflect research and interventions with children, and anti-bullying efforts that are effective with children appear to be much less effective with adolescents, so there is a need to investigate bullying experiences in adolescence.Each of the three papers in this dissertation investigates bullying in a different social context: (1) peer bystander reactions to bullying, (2) bullying by teachers, and (3) bullying within dating relationships. All three studies drew upon data from the statewide administration of school climate surveys in Virginia secondary schools.The first paper linked student attitudes toward peer aggression with bystander reactions to bullying. Newer bully prevention programs focus on encouraging students to be upstanders by teaching students that bullying is a group problem and to practice positive interventions by standing up to bullies. Consequently, it is important to understand beliefs and attitudes towards aggression that are associated with bystander behaviors that may encourage or discourage bullying. This study hypothesized that students who endorsed attitudes that aggression leads to more popularity and is acceptable would be more likely to reinforce bullying and less likely to stand up to stop it. In a sample of 28,765 middle school students we asked about their responses to recent bullying and classified three group of bystanders: upstanders (48%), reinforcers (7%), and passive bystanders (45%). Multi-level logistic regressions indicated that even though the prevalence of reinforcing behavior was generally low, students with higher levels of aggressive attitudes were more likely to encourage bullying. Conversely, higher aggressive attitudes made students less likely to be upstanders. A school-level analysis found that schools where aggressive attitudes are more widely shared had lower numbers of upstanders. These findings suggest that school-based interventions that target student beliefs and norms about aggression may be critical to the effectiveness of anti-bullying programs.The second study compared the prevalence and school adjustment of students bullied by teachers versus peers. Assessing teacher-student interactions is especially important in adolescence because it is a period when students begin to have relationships with a greater number of teachers and relate to them in a more independent and assertive manner. Notably, negative teacher-student interactions in secondary school contribute to poorer school adjustment. In contrast to bullying by peers, bullying by teachers has received little attention and is rarely included in the measurement of bullying. In a sample of 56,508 middle school students, a smaller proportion of students reported bullying by teachers (4%) versus bullying by peers (11%). In comparison to students who reported no bullying, students bullied by teachers were significantly more likely to report lower school engagement and...