This article presents the treatment of a 15-year-old hospitalized girl suffering for over 3 years with total mutism and school refusal. It explores the role of humor in this treatment, illustrating how it can serve to regulate a patient’s sense of anxiety and sensitivity to arousal. The therapist appreciates his patient’s efforts to protect herself and keeps in mind not to over-stimulate her. He uses humor to engage and protect her from feeling hurt. Finally, the patient initiates humorous exchanges with the therapist. Their shared use of humor helps the patient to expand her scope of activity.