Although there is agreement that well-being in school matters - for example, for student achievement, teacher optimal functioning, and school effectiveness - a more profound understanding is needed about the predictors, effects, and ways of promoting well-being in school. This topical volume presents up-to-date research on the role of well-being in school from the fields of educational sciences, educational psychology, and health science. The contributions investigate both teacher well-being and student well-being in different countries and by using various advanced methods. Importantly, well-being in school is understood in these articles as a multidimensional construct that takes the complexity of the term well-being and the educational setting into account. Accordingly, the contributors explore a range of approaches and instruments of how well-being in school can be investigated and discuss the benefits for individuals, schools, and educational systems in promoting well-being. The findings support the prominent role of well-being for students' and teachers' lives and encourage further research on well-being in school as there is a need for much more scientific knowledge in both theory and practice.