Objective: To assess the association between bullying behavior and depression, suicidal ideation, and suicide attempts among adolescents. Method: A self-report survey was completed by 9th-through 12th-grade students (n = 2342) in six New York State high schools from 2002 through 2004. Regression analyses were conducted to examine the association between being victimized and bullying others with depression, ideation, and attempts. Results: Approximately 9% of the sample reported being victimized frequently, and 13% reported bullying others frequently. Frequent exposure to victimization or bullying others was related to high risks of depression, ideation, and suicide attempts compared with adolescents not involved in bullying behavior. Infrequent involvement in bullying behavior also was related to increased risk of depression and suicidality, particularly among girls. The findings indicate that both victims and bullies are at high risk and that the most troubled adolescents are those who are both victims and bullies. Psychopathology was associated with bullying behavior both in and away from school. Conclusions: Victimization and bullying are potential risk factors for adolescent depression and suicidality. In evaluations of students involved in bullying behavior, it is important to assess depression and suicidality. (Contains 4 tables.)