Adjunctive strategies that effectively incorporate adolescents’ developmental needs may augment the therapeutic benefits of CBT for adolescents with ADHD. This preliminary study evaluated a combined CBT and music-based treatment designed to enhance emotion-regulation skills in adolescents with ADHD. Utilizing a single-case experimental design, eight adolescents with ADHD were assigned to a 3-week baseline assessment phase followed by 12 weekly individual sessions of treatment and a 2-month follow-up phase. The intervention was effective in reducing the core symptoms of ADHD such that participants showed an increase in adaptive emotion-regulation strategies (cognitive reappraisal) and decrease in maladaptive emotion-regulation strategies (expressive suppression). The intervention was also found to be highly acceptable to participants. The findings provide initial support for combining standard CBT with music-based treatment designed to enhance emotion-regulation skills, and add to the growing body of literature showing that adjunctive strategies can augment the therapeutic benefits of CBT for adolescents with ADHD.