This paper presents seven strong claims about successful school leadership, supported by robust empirical evidence. The authors, Kenneth Leithwood, Christopher Day, Pam Sammons, Alma Harris, and David Hopkins, argue that school leadership is second only to classroom teaching in influencing pupil learning. They identify five sources of evidence to support this claim, emphasizing the catalytic role of leadership in driving organizational change and improving student achievement. The second claim states that successful leaders share a common repertoire of basic leadership practices, which include building vision and setting directions, understanding and developing people, redesigning the organization, and managing the teaching and learning program. These practices are supported by evidence from both school and non-school contexts, with specific behaviors aligned with a widely recognized managerial taxonomy. The third claim highlights that the application of these leadership practices is contextually sensitive rather than rigidly prescribed. Successful leaders adapt their approach to fit the unique needs and conditions of their schools, demonstrating a high degree of flexibility and adaptability. The fourth claim asserts that school leaders improve teaching and learning indirectly by influencing staff motivation, commitment, and working conditions. This influence is mediated through the quality of these factors, which in turn affects classroom practices and ultimately student outcomes. The fifth claim suggests that school leadership has a greater impact on schools and pupils when it is widely distributed, involving multiple sources of leadership rather than being concentrated in a single individual. This distribution enhances the effectiveness of leadership practices and their impact on student achievement. The sixth claim notes that certain patterns of leadership distribution are more effective than others, with schools that achieve high levels of student achievement often having a more balanced and collaborative approach to leadership. The seventh claim identifies a small set of personal traits that explain a significant portion of the variation in leadership effectiveness. These traits include open-mindedness, flexibility, persistence, resilience, and optimism, which are particularly important in challenging circumstances. The authors conclude by emphasizing the importance of building on existing knowledge to inform policy and practice, and they outline plans for a large-scale empirical study to further explore these claims.This paper presents seven strong claims about successful school leadership, supported by robust empirical evidence. The authors, Kenneth Leithwood, Christopher Day, Pam Sammons, Alma Harris, and David Hopkins, argue that school leadership is second only to classroom teaching in influencing pupil learning. They identify five sources of evidence to support this claim, emphasizing the catalytic role of leadership in driving organizational change and improving student achievement. The second claim states that successful leaders share a common repertoire of basic leadership practices, which include building vision and setting directions, understanding and developing people, redesigning the organization, and managing the teaching and learning program. These practices are supported by evidence from both school and non-school contexts, with specific behaviors aligned with a widely recognized managerial taxonomy. The third claim highlights that the application of these leadership practices is contextually sensitive rather than rigidly prescribed. Successful leaders adapt their approach to fit the unique needs and conditions of their schools, demonstrating a high degree of flexibility and adaptability. The fourth claim asserts that school leaders improve teaching and learning indirectly by influencing staff motivation, commitment, and working conditions. This influence is mediated through the quality of these factors, which in turn affects classroom practices and ultimately student outcomes. The fifth claim suggests that school leadership has a greater impact on schools and pupils when it is widely distributed, involving multiple sources of leadership rather than being concentrated in a single individual. This distribution enhances the effectiveness of leadership practices and their impact on student achievement. The sixth claim notes that certain patterns of leadership distribution are more effective than others, with schools that achieve high levels of student achievement often having a more balanced and collaborative approach to leadership. The seventh claim identifies a small set of personal traits that explain a significant portion of the variation in leadership effectiveness. These traits include open-mindedness, flexibility, persistence, resilience, and optimism, which are particularly important in challenging circumstances. The authors conclude by emphasizing the importance of building on existing knowledge to inform policy and practice, and they outline plans for a large-scale empirical study to further explore these claims.