Bullying in school is a major social problem with severe consequences to physical and mental health, and it has been implicated in the most severe forms of school violence. Schools are in need of effective programs to reduce bullying and improve school safety. Bully-Proofing Your School (BPYS) is a school-based intervention program designed to reduce bullying and school violence; it differs from other anti-bullying programs by providing teachers with a specific curriculum that can be implemented in the classroom. The present study is an evaluation of BPYS at the elementary school and middle school level.