Using a novel approach to assess attachment to therapist from patient narratives (Patient Attachment to Therapist Rating Scale; PAT-RS), we investigated the relationships between secure attachment to therapist, patient-rated alliance, and outcome in a sample of 70 young adults treated with psychoanalytic psychotherapy. A series of linear mixed-effects models, controlling for length of therapy and therapist effects, indicated that secure attachment to therapist at termination was associated with improvement in symptoms, global functioning, and interpersonal problems. After controlling for the alliance, these relationships were maintained in terms of symptoms and global functioning. Further, for the follow-up period, we found a suppression effect indicating that secure attachment to therapist predicted continued improvement in global functioning, whereas the alliance predicted deterioration when both variables were modeled together. Although limited by the correlational design, this study suggests that the development of a secure attachment to therapist is associated with treatment gains as well as predictive of posttreatment improvement in functioning. Future research should investigate the temporal development of attachment to therapist and its interaction with alliance and outcome more closely. To ensure differentiation from patient-rated alliance, observer-based measurement of attachment to therapist should be considered.