The World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) are responsible for monitoring global progress towards water, sanitation and hygiene (WASH) related Sustainable Development Goal (SDG) targets. The global effort to achieve sanitation and water for all by 2030 is extending beyond the household to include institutional settings, such as schools, healthcare facilities and workplaces. This joint report is the first comprehensive global assessment of WASH in schools and establishes a baseline for the Sustainable Development Goal (SDG) period.