Background & Aims: Psychodrama is a form of human development which explores, through dramatic action, the problems, issues, concerns, dreams and highest aspirations of people, groups, systems and organizations. It is mostly used as a group work method. This research was to study the effectiveness of psychodrama group therapy on increasing the individual self-differentiation from the family of origin on female nursing students.Materials & Methods: The samples consisted of twenty female university students being divided into an experimental and a control group through cluster sampling. The experimental group was treated with twelve psychodrama group sessions (1.5 hour per session) the control group received no treatment. Related data were gathered using a questioner and then were analyzed by descriptive statistics and T-test. Results: Psychodrama group therapy increased students’ overall scale and four subscales of the questionnaire. It enhanced participants' emotional responsiveness and helped to discover the true self avoiding emotional triggering.Conclusion: Psychodrama group therapy was effective on increasing self-differentiation of nursing students.