Childhood is a crucial period in life. The things that we learn, do, and experience in childhood play a critical role in shaping who we are and who we become, and can leave lasting impressions on our lives for years to come. However, not all children have the same opportunities to enjoy good childhoods and to learn and grow in ways that set them up well for adult life. Children from socially and economically disadvantaged backgrounds are at particular risk, as this paper shows. Built using a series of key comparative indicators from the OECD Child Well being Dashboard, this paper examines how the well being of children from disadvantaged backgrounds compares both across OECD countries and relative to their more advantaged peers. Results highlight how growing up at the bottom end of the socio economic ladder leads to poorer outcomes in almost all well being areas, and how these well being inequalities are rooted in the poorer environments that disadvantaged children face at home, in school, and in the community.