This report presents the results of the sixth data-collection wave of the European School Survey Project on Alcohol and Other Drugs (ESPAD) and marks the 20th anniversary of ESPAD data collection (1995-2015). It is based on information provided by 96 043 students from 35 European countries, 24 of them being Member States of the European Union. About 600 000 students have participated in the successive ESPAD data-collection waves, making the project the most extensive, harmonised data collection on substance use in Europe.