Objective-To identify an association between involvement in bullying and problems in school.Study design-This was a cross-sectional study of 5391 students in grades 7, 9, and 11 in an urban public school district. The main outcome measure was involvement in bullying. Secondary outcomes included attendance, grade point average, psychosocial distress, and perceived acceptability of carrying guns to school.Results-Of the 5391 children surveyed, 26% were involved in bullying either as victim, bully, or both (bully-victim). All 3 groups were significantly more likely than bystanders to feel unsafe at school and sad most days. Victims and bully-victims were more likely to say they are "no good." Victims were more likely to feel that they "do not belong" in their school. The odds of being a victim (vs a bystander) were 10% lower for every 1 point increase in grade point average. Bully-victims were more likely to say that it is "not wrong" to take a gun to school.Conclusions-Associations between involvement in bullying and academic achievement, psychological distress, and the belief that it is not wrong to take a gun to school reinforce the notion that school environment is interrelated with mental health and school success.Bullying is defined as any repeated negative activity or aggression intended to harm or bother someone who is perceived by peers as being less physically or psychologically powerful than the aggressor. 1 Of particular concern is that bullying may have an adverse impact on victims' scholastic achievement, desire to attend school, and psychological health. 2 In 2000, Nansel et al 3 found a prevalence of bullying involvement (as bully, victim, or both [bully-victim]) among American teens and preteens of approximately 30%. But although this study found a significant association between bullying involvement and lower self-reported academic achievement, it did not use objective measures of academic achievement. Two other studies found a relationship between victim status and lower grade point averages. 4,5 Results from studies of other age groups in other countries vary. [6][7][8] Between 1994 and 1999, 220 school-associated violent deaths occurred in the United States, of which 172 were committed by students. Analysis revealed that the offending students were 2.6 times more likely to have been bullied than their victims. 9 One US national study reported that during 1 month in 2001, 2.7 million students carried a weapon to school. In that study, carrying weapons was associated both with being a bully and with being a victim 19,20 Variations in culture, school variables, or socioeconomic factors may account for these differences. [19][20][21] The present study arose from an offer by a US urban school district to allow the authors to analyze the results of a survey designed to assess and improve the school climate. The goal was to characterize bullies, victims, and bully-victims as completely as possible given the available information. We identified the opportunity to answer the following specific...