Objective: This study reassessed adolescents and young adults (15-22 years old) who received individually tailored multimodal treatment for ADHD (behavior therapy and/or stimulant medication) during childhood 6 to 12 years after treatment (M = 8.8 years, SD = 1.6). Method: All participants (N = 75) provided information about their social functioning. Most parents (83%) completed behavior rating scales. Results: Participants demonstrated significant improvement in behavior during the follow-up period with effect sizes on ADHD symptoms of d = 1.2 and 68% of the former patients in the normal range at follow-up. Participants reported elevated rates of grade retention (51%), school dropout (13%), special education service use (17%), school change (47%), and conviction (16%), but few were unemployed (4%). Conclusion: This study provides evidence that the effects of individually tailored multimodal treatment for ADHD in childhood are maintained into adolescence and young adulthood. No hints could be found that continued medication results in a more favorable long-term outcome.