Mental disorders are a leading burden of disease for adolescents. Yet, data on the prevalence of adolescent mental health conditions remain sparse, especially in low- and middle-income countries (LMICs). These data are urgently needed to guide strategic actions to address the burden of mental health problems among adolescents through effective policies and programs. UNICEF has made it a priority to address this data gap by investing in the development of measurement tools and working with partners on the population-level measurement and programming for mental health of adolescents and young people.