Health Behaviour in School-aged Children (HBSC) is a cross-sectional survey conducted every four years since 1982 under the auspices of the World Health Organization’s Regional Office for Europe among students aged 11, 13, and 15. It aims to better understand the health and well-being of young people, their health behaviors, and their determinants through anonymous self-administered questionnaires completed in the classroom. Conducted in more than forty countries using a standardized methodology and questionnaire, it involved approximately 200,000 students in 2014. This document presents the general methodology of the survey.