School closures to mitigate the spread of COVID-19 have caused unprecedented disruption for nearly 1.6 billion learners across the globe. Beyond alarming effects on learning loss and school dropout, they pose an immediate and long-term threat to gender equality, with gender-specific effects on health, well-being and protection. This publication exposes these impacts and calls for effective strategies to ensure education continuity, promote gender equality and improve lives and futures. Through a review of published research, a global survey of actions taken by organizations in favour of gender equality in education, and in-depth data collection in five countries, UNESCO and its partners underline the challenges faced by children and young people to continue learning, and to return to school safely. When schools shut also showcases the efforts made by governments and the international community to mitigate harm and safeguard progress towards gender equality in and through education. While it is too soon to grasp the full scope of the impact of school closures, the publication sets out early evidence from across different contexts globally on how girls and boys have been participating in remote learning, planning for the return to school, and coping with mental and physical health challenges during the closures. It is a call to governments and their partners to put gender at the centre of education recovery to tackle declining participation and low return-to-school rates. When schools shut is a timely reminder that schools are essential sites not only for learning, but also lifelines when it comes to health, well-being and protection of all learners.