Objective: The aim of the study was to validate the Norwegian version of the Adult Attention-Deficit/Hyperactivity Disorder Quality of Life (AAQoL) scale and to explore Quality of Life (QoL) and functional outcomes in adults with ADHD. Method: A total of 313 adults with ADHD participated in the study. Data were collected from medical records and self-report questionnaires. Confirmatory factor analysis was performed to assess the model fit of the translated AAQoL. Chi-square statistics and t tests were used to investigate sample characteristics. Results: The analyses showed acceptable model fit between data and the model. Chi square = 863.179 (371 df, p < .0000), root mean square error of approximation (RMSEA) = 0.069 (90% confidence interval [CI]), comparative fit index (CFI) = 0.873, and Tucker–Lewis index (TLI) = 0.821. Cronbach’s alpha range for the scales was .761 to .869. The sample was characterized by poor QoL and impairment. Conclusion: The translated AAQoL is showing good initial indications of validity with acceptable psychometric properties in the sample. ADHD was associated with impairments in QoL, symptoms, and functional outcomes.