This chapter describes school as both a crucial learning environment for students and a crucial working environment for teachers. Schools where both students and teachers flourish are defined as positive schools. Using the theoretical framework of the “engine model of well-being” that focuses on inputs, processes, and outcomes of human well-being, flourishing students and teachers are described as individuals who, for example, experience positive emotions, are engaged in schooling, and demonstrate positive accomplishments (Jayawickreme, Forgeard, & Seligman, 2012; Seligman, 2011). Research findings on the relations between, for example, input variables and process variables of students, or process variables and outcome variables of teachers, are summarized, showing the complex interplay between teachers’ and students’ well-being. Furthermore, examples of formal programs designed to foster well-being are presented and discussed with respect to the engine model. Finally, concluding remarks are given, and future directions for research are discussed.