Adolescents with ADHD have planning problems, often affecting school- and social functioning. Evidence-based treatments for adolescents with ADHD are scarce and treatment drop-out rates are substantial. The effectiveness of two new, individual, short-term cognitive behavioral therapies (CBT) was investigated: One with an aim on improving planning skills and one solution-focused treatment (SFT) without such an aim. Motivational Interviewing elements were added to both treatments to enhance treatment compliance. In a multi-center randomized clinical trial, 159 adolescents (12-17 years) with ADHD were randomly assigned to one of both treatments. Pre-, post- and 3-month follow-up data were gathered on five domains: Parent-rated ADHD, planning problems and executive functioning (primary outcomes), neuropsychological measures of planning, comorbid symptoms, general functioning, and teacher measures. Attrition was low in both treatments (5%). Adolescents improved significantly between pre- and post-test with large effect sizes on all domains. Improvements remained stable or continued to improve from post-test to follow-up, also when controlling for medication use. Marginally significant differences were found in favor of the planning-focused treatment: parents and therapists evaluated this treatment more positively than SFT and the planning-focused treatment showed more reduction of parent-rated planning problems. Two new CBTs with integrated motivational components were feasible and attrition was low. ADHD symptoms and co-existing problems of the adolescents improved from pre-test to 3 months after treatment. As the planning-focused treatment was evaluated more positive and had marginal additional beneficial effects to SFT, especially planning-focused CBT seems promising to fill the gap in available treatments for adolescents with ADHD.