This paper describes the research findings that formed part of a professional doctorate in Child Psychoanalytic Psychotherapy. It explores the impact of unresolved mourning following parental death in early adolescence on subsequent adolescent development. Via reference to a single case study, it describes emergent and overlapping themes related both to the bereavement process and adolescent development, and links the themes with psychoanalytic theoretical research in both adolescent development and bereavement. It considers how these themes changed over the course of an intensive psychotherapeutic treatment.