Bullying in schools has become an issue of major importance among educators. However, interventions to reduce bullying have enjoyed only modest and limited success. Ken Rigby examines five different explanations for bullying. Each has had some impact on school policies and practices. The strengths and limitations of the different explanations are examined. It is concluded that none of them provides a comprehensive explanation for school-based bullying and that their value lies especially in suggesting actions that may be taken by schools in addressing particular bully/victim problems.