School autonomy has become increasingly significant in the politics of education, as well as a central feature of education systems’ reform policies in Australia and globally. This review examines the spectrum of evidence on the impact of school autonomy on student academic achievement, and the features of autonomy that improve or constrain achievement, and discusses the implications of these findings for future policy. There is no definitive or simple conclusion from assessing the impact of autonomy on student achievement, but neither does the evidence reject the contribution of autonomy. Rather, the evidence points to autonomy as a key and necessary component of a mature and high-performing system, as it is in other areas of public administration. However, the wider institutional context matters, and parallel policies like accountability and leadership development need to be in place. Crucially, and counter to popular conception, more rather than less systemic support is needed for the potential of school autonomy to be realised.