The forgotten dream proved central to the early development of Sigmund Freud's psychoanalytic technique in The Interpretation of Dreams (1900). However, little attention has been paid to the shifting uses of forgotten dreams within psychotherapeutic practice over the course of the twentieth century. This paper argues that post-war psychotherapists in London, both Jungian and Freudian, developed a range of subtly different approaches to dealing with their patients' forgotten dreams. Theoretical commitments and institutional cultures shaped the work of practitioners including Donald Winnicott, Melanie Klein, Anna Freud, and Edward Griffith. By drawing on diaries and case notes, this paper also identifies the active role played by patients in negotiating the mechanics of therapy, and the appropriate response to a forgotten dream. This suggests a broader need for a detailed social history of post-Freudian psychotherapeutic technique, one that recognises the demands of both patients and practitioners.