This paper illustrates the application of Hildegard Peplau's Interpersonal Theory of Nursing to group psychotherapy. The phases of the nurse-patient relationship, including orientation, identification, exploitation and resolution, are described as they relate to group psychotherapy, and clinical examples are presented. The clinical examples also demonstrate the patient's movement in group therapy through the steps of the learning process: observation, description, analysis, formulation, validation, testing, integration and utilization. Finally, the roles of the nurse including stranger, resource person, teacher, leader, surrogate and counsellor are described as they occur in group psychotherapy.