How to hold autonomous schools and school governing boards accountable for their decisions and performance has become a particularly pressing question for central governments in many OECD countries. Increasing complexity in education systems has led to a greater degree of freedom in decision making for many local authorities, school governing boards and schools. However despite this increasing decentralisation, central governments are still held responsible by the general public for ensuring high quality education. During the last ten years, school accountability has become a critical topic, triggered by the results of international benchmarks such as the Programme for International Student Assessment (PISA) and Trends in International Mathematics and Science Study (TIMSS). This paper analyses trends in accountability mechanisms and processes and argues that vertical measures of accountability, that is, regulatory and school performance accountability, can be usefully augmented by horizontal measures involving multiple stakeholders. This system of multiple school accountability aims to efficiently and effectively take into account the nuanced nature and purposes of education. By combining various forms of accountability, it has the potential to enhance the overall education system, policy for reform, and therefore ultimately improve the quality of education.