School bullying has been a major health and safety concern for teachers and students, which calls for effective strategies to address the issue. In this study, we explored individual and organisational factors that improve the effects of teachers’ use of anti‐bullying strategies in reducing or preventing student bullying. Specifically, we examined the moderating role of teachers’ psychological ownership of their school's anti‐bullying system in the relationship between teacher‐reported use of anti‐bullying strategies and student‐reported bullying incidents. We also investigated how principals’ bullying prevention leadership, rated by a group of directors who are the immediate subordinates of these principals, inspires teachers’ psychological ownership of their school's anti‐bullying system through building teachers’ shared perceptions of a bullying prevention climate. Results of multilevel analyses of multisource data from 2,123 teachers, 407 directors, and 15,967 students in 110 junior and senior high schools indicated that the impact of teacher‐reported use of anti‐bullying strategies on student‐reported bullying incidents was strengthened when teachers have a high level of psychological ownership of their school's anti‐bullying system. Further, principals’ bullying prevention leadership was significantly positively related to teachers’ psychological ownership of their school's anti‐bullying system through teachers’ shared perceptions of a bullying prevention climate.