Using evidence from a series of studies carried out over 20 years, this article explores ways of developing schools that are effective for all children and young people. The argument developed is intended to challenge those leading school improvement to return to their historical purpose, that of ensuring a sound education for every child. The authors argue that in order to achieve this it is necessary to complement within-school developments with efforts that link schools with one another and with their wider communities. This means that school improvement processes have to be nested within locally led efforts to make school systems more equitable and to link the work of schools with area strategies for tackling wider inequities and, ultimately, with national policies aimed at creating a fairer society. This article considers the implications of this analysis for the work of senior staff at all levels of the education system.