Objective: ADHD is known to be associated with psychiatric comorbidities and psychosocial adversities in the long term. The existing literature is focused on predominantly Western samples. There are no studies evaluating longterm functionality of youth diagnosed with ADHD in Turkey. Methods: Patients diagnosed with ADHD at a study center in between 2011 and 2012 were contacted and current functionality was assessed via phone interviews. Univariate and bivariate analyses were conducted to determine correlates of functioning. Sequential logistic regression analyses were conducted to evaluate predictors of still receiving treatment for ADHD, improvement in attention/ academics, improvement in behavior and in peer relationships. p was set at 0.05. Results: Information on functioning of 433 patients (78.3% male) could be collected. Male patients with ADHD tended to be more frequently under treatment at follow-up and they displayed behavior problems at follow-up significantly more frequently. Legal problems were reported in 3.7% and substance use in 2.3%. Discussion: Treatment for ADHD lasting at least 3 years predicted improved functioning and less psychosocial adversity. Earlier diagnosis of ADHD and longer treatment appears to protect against psychosocial adversity also in Turkish samples. Multi-center studies from Turkey with larger samples are needed.