This project investigates the impact of the dynamic approach to school improvement (DASI) aiming to help schools face and reduce bullying through integrating research on bullying with educational effectiveness research (EER). A network of approximately 15 schools in each participating country (i.e., Belgium, Cyprus, England, Greece, and The Netherlands) received support to use DASI in order to improve the functioning of school factors included in the dynamic model of educational effectiveness which are associated with reduction of bullying. The Revised Olweus Bully/Victim Questionnaire was administered to students of the experimental (n = 1461) and control (n = 1535) group at the beginning and at the end of the intervention. With the use of multilevel modelling techniques, it was found that schools which made use of DASI were able to reduce bullying at a significantly higher level than the schools of the control group. Implications for the development of effective policies and practices in reducing bullying are drawn.