Students spend significantly more time in school compared to any other formal institution during their lives; therefore, mental health in schools has attracted a lot of attention in recent years. According to Seligman et al. (2009), positive psychology in school is a response to the gap between what people want for their children and what schools teach. That is, most parents want their children to be happy, healthy, and confident, but schools only focus on achievement, discipline, and academic skills. These are of course important, but so are positive mental health outcomes. To fix this gap, schools must teach achievement and accomplishment along with positive psychology-informed mental health skills. In other words, positive education aims to bring positive psychology’s goals of well-being and mental health support for everyone into the school setting. Psychological interventions have been around in schools since at least the 1930s. Therefore, it makes sense to supplement the already-existing traditional psychology in schools with positive psychology. In the field of psychology, positive psychology interventions are defined as those aimed at raising positive feelings, positive thoughts, and positive behaviour and increasing well-being. Positive Psychology Interventions in schools have been shown to improve mental health and well-being outcomes for students. Recent research has confirmed the same results, as offering emotional support early in a school year can lead to improved instructional quality later in that school year. In other words, positive school psychology interventions offer a focus on mental health in order to set the stage and give students the opportunity for academic achievement.  Since the beginning of the positive psychology movement, the application of its assumptions in schools has been one of the movement’s main pillars. The objective of the book is to help counsellors, teachers, and school leaders engage in a positive psychology research-based practice in schools.