Objective: We assessed factors influencing quality of life (QoL) in adults with ADHD. Method: QoL, traumatic childhood experiences, and depression were assessed using the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), Childhood Trauma Questionnaire (CTQ), and Beck Depression Inventory (BDI), respectively, in 60 adult ADHD outpatients and 60 age- and gender-matched controls. Results: Emotional neglect or abuse had occurred significantly more often during childhood in adults with ADHD. Depressive symptoms were rated significantly higher by ADHD patients. QoL was significantly lower in adults with ADHD, and the variables depression, ADHD symptom severity, and traumatic load, accounted for ~60% of variance in overall QoL. Conclusion: QoL is significantly reduced in adult ADHD patients. Depressive symptoms and traumatic childhood experiences influence QoL. Treatment for adult ADHD patients should take the high interdependence of depressive symptoms, childhood trauma, and QoL into consideration.