Traumatic events, including sexual abuse, experiencing or witnessing violence, and natural disasters, are common among adolescents. A significant number of adolescents go on to develop posttraumatic stress disorder (PTSD), which can have a severe negative impact on well-being and functioning. These adolescents require professional help to free themselves of PTSD symptoms and reclaim their lives. This therapist guide presents a proven treatment for PTSD that has been adapted for the adolescent population. The program applies the principles of Prolonged Exposure (PE) to help adolescents emotionally process their traumatic experiences. A four-phase treatment, adolescents complete each module at their own rate of progress. The pre-treatment preparation phase includes modules on motivational interviewing and case management. During the first treatment phase, modules cover the rationale for treatment, information-gathering about the trauma, and common reactions to trauma. Modules in the next phase, exposures, comprise the core of the treatment. By systematically confronting situations associated with the trauma, adolescents overcome avoidance and fear. Recounting the memory of the traumatic event helps adolescents distinguish the past from the present and promotes feelings of mastery. The final phase involves modules on relapse prevention and treatment termination. This therapist guide considers the adolescent's age and developmental level and includes developmentally appropriate materials. It offers additional guidance on tailoring the treatment to each client's unique situation, including trauma type and family structure. Handouts for parents are provided in an appendix. The corresponding teen workbook contains information on each module and forms for adolescent use. Comprehensive and effective, this program is an invaluable contribution to the treatment of adolescents with PTSD.