Every child has the right to health, education and protection, and every society has a stake in expanding children's opportunities in life. Yet, around the world, millions of children are denied a fair chance for no reason other than the country, gender or circumstances into which they are born. The "State of the World's Children 2016" argues that progress for the most disadvantaged children is not only a moral, but also a strategic imperative. Stakeholders have a clear choice to make: invest in accelerated progress for the children being left behind, or face the consequences of a far more divided world by 2030. At the start of a new development agenda, the report concludes with a set of recommendations to help chart the course towards a more equitable world. A Perspectives section offers: (1) A fair chance for girls -- End child marriage (Angélique Kidjo); (2) Give children a chance (Gordon Brown); and (3) What are we waiting for? Sustainable societies begin with children (Kailash Satyarthi).