This report looks at how, despite major strides made towards poverty reduction and towards achieving the millennium development goals (MDGs), increasing inequality in many countries in the last two decades has hampered greater progress. It outlines how some countries – through proven policies and interventions – have managed to reduce gross inequalities and deliver better outcomes for their children, laying stronger foundations for the future. The report starts to provide an overview of the progress made towards achieving the MDGs, and looks at one of its main blind-spots – inequality – which, the report argues, has prematurely closed off opportunities to make further progress in reducing poverty and improving child well-being, especially in countries where inequality is most pervasive. This report explains why children are particularly vulnerable to the damaging effects of inequality. It argues that, because of their particular life-stage, short-term deprivations (resulting from gross inequalities) or psychosocial effects of big disparities experienced during childhood can have lifelong consequences. The report looks at how children are more affected by inequality than the general population – on the basis of quantitative analysis on income inequality in 32 low- and middle-income countries. The report then assesses the effects that inequality has on child development outcomes on the basis of eight case studies conducted for this research, in partnership with local research institutions, in Brazil, Canada, China, Ghana, India, Indonesia, Nigeria and the UK. Finally, the report looks at the policies and interventions that have successfully managed to reduce inequalities and deliver better outcomes for children. The report concludes with four recommendations to seize the major opportunity presented by the post-2015 framework, and calls upon the international community to place inequality front and centre.