UNESCO’s policy guide unpacks social and emotional learning (SEL) as a broadening of the educational process, from a focus on cognitive aspects to a balance between cognitive, social and emotional, and behavioural dimensions of learning, putting forward initial action ideas to guide its systematic mainstreaming in education. It builds on and extends previous work undertaken by UNESCO on SEL from the perspective of Global Citizenship Education (GCED) and Education for Sustainable Development (ESD), Building Strong Foundations for Health and Well-being Education, the Happy Schools Framework, and in multiple UNESCO Offices and Institutes.