School leaders are under considerable pressure to demonstrate the contribution of their work to school improvement, which has resulted in the creation of a wide range of literature which addresses leadership in the context of school improvement. This review pays particular attention to issues including transformational leadership, instructional/pedagogical leadership and distributed leadership. The evidence examined by this review indicates that effective school leadership is important but, in isolation, is not a sufficient condition for successful schools. The review draws particular attention to two concepts of leadership: instructional/pedagogical and transformational. While there is evidence that instructional/pedagogical leadership has been shown to be important for promoting better academic outcomes for students, it is concluded that the two forms of leadership are not mutually exclusive. A combination of strategies can be most beneficial in ensuring school success and most leadership effects operate indirectly to promote student outcomes by supporting and enhancing conditions for teaching and learning through direct impacts on teachers and their work. School leaders, particularly principals, have a key role to play in setting direction and creating a positive school culture including the proactive school mindset, and supporting and enhancing staff motivation and commitment needed to foster improvement and promote success for schools in challenging circumstances. The challenges facing school leaders include: (1) ensuring consistently good teaching and learning; (2) integrating a sound grasp of basic knowledge and skills within a broad and balanced curriculum; (3) managing behaviour and attendance; (4) strategically managing resources and the environment; (5) building the school as a professional learning community; and (6) developing partnerships beyond the school to encourage parental support for learning and new learning opportunities. The key dimensions of successful leadership are identified as: (1) defining the vision, values and direction; (2) improving conditions for teaching and learning; (3) redesigning the organisation: aligning roles and responsibilities; (4) enhancing teaching and learning; (5) redesigning and enriching the curriculum; (6) enhancing teacher quality (including succession planning); (7) building relationships inside the school community; (8) building relationships outside the school community; and (9) placing an emphasis on common values.