The new Sustainable Development Goals, which replaced the Millennium Development Goals, include strong targets to reduce violence against children, improve health, nutrition and access to education, and many other aspects in life that are important in a child’s development. World leaders agreed that the new development agenda would “leave no one behind”. Yet, as it stands, the new Goals will leave children living without parents and outside families, in institutions or orphanages, very far behind. In September 2015, we joined an advocacy movement to call on the United Nations and its member states to change this. To date, this joint open letter has been signed by over 250 organisations, NGOs, academics, and others from around the world, and the movement keeps growing.