Objective: Self-harm is an important public health issue in the UK. Young people who self-harm frequently feel misunderstood, and unable to access help. Improving understanding is key to informing the development and delivery of effective treatments and services. Methods: In this qualitative study, we interviewed nine adolescent girls (13–17 years old) with recurrent self-harm, recruited from NHS specialist child and adolescent mental health services. Data were analysed using Interpretative Phenomenological Analysis (IPA). Results: Findings revealed that self-harm is experienced as powerful mental and physical urges, sated only by self-harming, suggesting that self-harm could be considered a compulsive rather than impulsive disorder, representing a new perspective on the behaviour. Five themes emerged: emotion regulation; an addictive urge; self-harm to survive; interpersonal triggers; interpersonal relationships, not mechanical distractors, reduce self-harm. Conclusions: This study provides further evidence that non-suicidal self-injury may be engaged in to reduce suicidal risk. Seeking the company of helpful friends or family members may reduce the urge to self-harm. Repetitive self-harm may be a compulsive behaviour.