Health equity enables everyone to have the best possible opportunity for good health regardless of their social circumstance. In this article we set out why it is so vital that this begins in childhood, particularly at a time when increased costs of living in many countries are exacerbating health inequities further. We examine the impact of addressing the social determinants of health at individual, population and systems levels, and why this is the business of all partners involved in the local health economy. In the UK, integrated care systems (ICS) are early in their development. In this short article, we describe the work of the Children and Young People's Health Equity Collaborative: a collaboration between children's charity Barnardo's, the Institute of Health Equity, Birmingham and Solihull ICS, Cheshire and Merseyside ICS, and South Yorkshire ICS. This details a three-year programme designed to establish enablers for this whole systems approach. This includes a Children and Young People's Health Equity Framework, a dynamic data measurement tool to direct action for longer term outcomes and supporting child health equity interventions. Children and young people's voice is central to our work, combining academic evidence with lived experience of what really matters to them.