Participation in education by three- and four-year-olds tends now to be high, though coverage is a third or less of the age group in several OECD countries. Early childhood education and care (ECEC) has been a growing priority in OECD countries, and the subject of past and ongoing OECD analysis. A major OECD review was published in 2006 – Starting Strong II: Early Childhood Education and Care – which has been followed up through an ongoing international network. There are wide differences between systems, including between those which have a strong “preparation for school” approach and those implementing a broader social pedagogy, between those with mainly public provision and those relying strongly on private household resources, as well as in the relative emphasis on education and childcare. ECEC can bring a wide range of benefits for children, parents and society at large, but the magnitude of benefits is conditional on quality. Therefore the OECD in 2012 released Starting Strong III: A Quality Toolbox for Early Childhood Education and Care, which serves as a reference guide and aims to encourage quality in ECEC. Additionally, the 2012 edition of Education at a Glance: OECD Indicators includes a new indicator on the state of early childhood education, providing a rich comparative insight into early childhood education systems around the world.