Body dysmorphic disorder (BDD) is a relatively common and severe disorder that typically onsets in adolescence, but often goes unrecognized. Despite BDD’s severity and early onset, treatment outcome research on adolescent BDD is scarce. Cognitive-behavioral therapy is the gold-standard psychosocial treatment for BDD in adults and has shown promise in adolescents. The current study examined the development and testing of a new CBT for adolescents with BDD. We tested feasibility, acceptability, and treatment outcome in a sample of 13 adolescents (mean age 15.23 years, range: 13–17) with primary BDD. Treatment was delivered in 12–22 weekly individual sessions. Standardized clinician ratings and self-report measures were used to assess BDD and related symptoms pre- and posttreatment and at 3- and 6-months follow-up. At posttreatment, BDD and related symptoms (e.g., insight, mood) were significantly improved. Scores on the Yale–Brown Obsessive Compulsive Scale for BDD indicated a 50% (intent-to-treat) and 68% (completer) improvement in BDD symptoms. Seventy-five percent of adolescents who started treatment and 100% of completers were considered treatment responders. Treatment gains were maintained at follow-up. High patient satisfaction ratings and patient feedback indicated that treatment was acceptable. This represents the largest study of a psychosocial treatment for adolescent BDD.