The Clinician's Manualand its accompanying workbook,I Believe in Me, Not OCB!are the first known manuals to combine cognitive behavioral therapy and applied behavior analysis to treat obsessive-compulsive behavior (OCB) in children and youth with autism.The Clinician's Manualserves as a practical guide for therapists, beginning with chapters that explain the theoretical underpinnings of OCBs, adaptations for autism, and guidance on clinical and functional behavioral assessment that are key to administering the nine treatment sessions that follow.Our evidence-based treatment incorporates functional behavioral assessment, CBT skills training, caregiver coaching, and social skills activities in a nine-week progressive program. Caregiver and child report data inform progress throughout the program. Generalization and maintenance are promoted through weekly caregiver coaching modules. Treatment can be delivered in a group or individual format and focuses on reducing OCBs with the ultimate goal of increasing quality of life.The manual provides all clinician, child, and caregiver instructions as well as materials to implement functional behavior-based CBT with precision. These manuals are a vital resource for clinicians working with autistic children and youth and their families.