This paper provides a short review of the evidence available for the success or otherwise of campaigns against bullying, with particular reference to secondary schools. It then goes on to describe a longitudinal study of the incidence of bullying and aggression in one secondary school in which a whole school campaign was mounted to reduce bullying and aggression. The very encouraging findings after two years are compatible with, although not as dramatic as those in a Norwegian study. They are in contrast with the findings of large scale intervention projects in two UK cities. Possible reasons for this contrast are discussed, such as length of intervention period, the way in which the survey methods were developed, ownership and perceived seriousness on the part of staff and the primary foci of tackling this problem. The occurrence of a Year 9 'hump' in reported bullying and aggression by cohorts in the school understudy is discussed in the light of other findings. Implications for practice are outlined in the conclusions.