Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent psychiatric disorder in children/adolescents. This study reviews available European-based studies of ADHD-related costs and applies the findings to the Netherlands to estimate annual national costs for children/adolescents from a societal perspective. A systematic literature search was conducted for primary studies in Europe, published January 1, 1990 through April 23, 2013. Per-person cost estimates were converted to 2012 Euros and used to estimate annual national ADHD-related costs based on the Dutch 2011 census, ADHD prevalence rates, family composition, and employment rates. Seven studies met the inclusion criteria. The average total ADHD-related costs ranged from €9,860 to 14,483 per patient and annual national costs were between €1,041 and €1,529 million (M). The largest cost category was education (€648 M), representing 62 and 42 % of the low- and high-value overall national estimates, respectively. By comparison, ADHD patient healthcare costs ranged between €84 M (8 %) and €377 M (25 %), and social services costs were €4.3 M (0.3-0.4 %). While the majority of the costs were incurred by ADHD patients themselves, €161 M (11-15 %) was healthcare costs to family members that were attributable to having an ADHD child/adolescent. In addition, productivity losses of family members were €143-€339 M (14-22 %). Despite uncertainties because of the small number of studies identified and the wide range in the national cost estimates, our results suggest that ADHD imposes a significant economic burden on multiple public sectors in Europe. The limited number of European-based studies examining the economic burden of ADHD highlights the need for more research in this area.