Early childhood development is a driving force for sustainable development due to its multiplier effects not only on children but also on the community and society at large. Access to ECEC alone is insufficient for achieving positive child outcomes – it must also be of high quality. This Brief aims to summarize the key points of ongoing debate on this issue, and outline some of the challenges faced by high-income countries. A step towards a more holistic monitoring of ECEC would be to develop a coherent national strategy that recognizes diversity while addressing disparities; to respond to the needs of both child and family through strong partnerships with parents and ECE practitioners; and to apply measurement tools that capture a child’s engagement rather than test readiness.