Depression is the fourth leading cause of adolescent illness and disability worldwide. A growing evidence base demonstrates that Short Term Psychoanalytic Psychotherapy [STPP] is an efficacious treatment for moderate to severe adolescent depression. However, with research in its infancy, key factors contributing to efficacy are unknown. Service users' lived experiences provide valuable insight in this area. This study aimed to elucidate what adolescents value in treatment by inductively exploring lived experiences of STPP. Five adolescents with the largest reduction in depressive symptoms scores between baseline and end of treatment, who had taken part in a large-scale randomized controlled trial, were sampled. In-depth interviews carried out soon after the end of therapy were analysed using Interpretative Phenomenological Analysis. Three superordinate themes were identified: "Therapy as a Transformational Process", "Explorative and Exposing: The Therapeutic Space" and "Being Heard and Working Together: The Therapeutic Relationship". Adolescents valued a process of collaborative exploration with the therapist which when it was achieved was felt to facilitate a deep-rooted transformation in self-perception. Additionally, they described how an adjustment was needed to the particular frame of a psychoanalytic therapy. However, not all participants with a good treatment outcome experienced therapy in this way, suggesting a potential gap between the quantitative assessment of outcomes, and the way young people experience and understand the change process. Clinical implications and directions for research are discussed.