We evaluated the feasibility of DBT training, adherence, and retention preparing for a randomized controlled trial of Dialectical Behavior Therapy (DBT) adapted for Norwegian adolescents engaging in self-harming behavior and diagnosed with features of borderline personality disorder. Therapists were intensively trained and evaluated for adherence. Adherence scores, treatment retention, and present and previous self-harm were assessed. Twenty-seven patients were included (mean age 15.7 years), all of them with recent self-harming behaviors and at least 3 features of Borderline Personality Disorder. Therapists were adherent and 21 (78%) patients completed the whole treatment. Three subjects reported self-harm at the end of treatment, and urges to self-harm decreased. At follow up, 7 of 10 subjects reported no self-harm. DBT was found to be well accepted and feasible. Randomized controlled trials are required to test the effectiveness of DBT for adolescents.