Deliberate self-harm in adolescents is an increasing clinical problem, but there is a limited understanding of the mechanisms causing or maintaining this behaviour. One proposed mechanism is that of dissociation. However, the role this mechanism may play is unclear: although some suggest that adolescents engage in self-harm to end the aversive experience of dissociation, others propose that self-harm is used to purposefully trigger a dissociative state to avoid emotional pain. This systematic review is the first to evaluate the available evidence regarding the relationship between dissociation and deliberate self-harm in adolescents (aged 18 or younger). Nineteen relevant studies were identified. These studies were limited by cross-sectional design and poor methods of measurement, but some important conclusions could be drawn. The majority of studies found a positive correlation between the severity of dissociation and the severity and frequency of deliberate self-harm in adolescents, and a small number of results suggest that dissociation mediates the relationship between childhood trauma and adolescent self-harm.