Self-harming behaviour is an increasing problem for families and health services. Over the past two decades a number of models to explain and treat self-harming behaviour have emerged. One such model arises from Dialectical Behaviour Therapy (DBT), which was originally developed and evaluated for the treatment of women diagnosed with Borderline Personality Disorder (BPD) in the community. This paper will review how the DBT model provides an understanding of self-harming behaviour and provide evidence for the efficacy of DBT. The DBT model suggests that self-harming behaviour arises as a strategy to manage overwhelming affect. Thus interventions aimed at increasing emotional regulation and problem-solving are likely to be effective in reducing self-harming behaviour.