The study found that for young children, attending a large school increased their risk for being victims of bullying. One possible explanation for this finding is that large schools in the United Kingdom may have a greater age range of pupils, increasing the risk for younger children to be bullied by older students. Experiencing problems with neighbors also increased the risk for being bullied at school. One possible explanation for this finding is that children who observe hostile interactions among adults and older youth in their neighborhoods imitate this behavior in interactions with peers. Family factors were uniquely associated with bullying. Witnessing domestic violence by 5 years old was associated with bullies. For victims of bullying, maltreatment in the home was a factor. These findings suggest intervention programs designed to reduce bullying and bullying victimization should focus not only on bullying behaviors and victimization at school, but also neighborhood manifestations of conflict and spousal and parent-to-parent interaction in the family. This study examined data on bullying obtained from the Environmental Risk Longitudinal Twin Study conducted in the United Kingdom. This study involves a nationally representative 1994-95 birth cohort of 2,232 children. Mother and teacher reports were used to identify children who had experienced bullying between the ages of 5 and 7 years old either as victims, bullies, or as both bullies and victims. Information on school characteristics was obtained from the Department for Children, Schools, and Families. Reports from mothers produced information on children’s neighborhoods and home environments. Reports from both mothers and teachers addressed children’s emotional and behavioral problems when they were 5 years old. 3 tables and 49 references