The early childhood learning trajectories provide a translation of evidence on how children develop, incorporated into a clear, engaging resource for early childhood teachers and educators. This report summarises the evidence base that informed their development. It aims to deepen understanding of the domains of learning and development that the learning trajectories cover and show how they relate to early childhood assessment tools. The learning trajectories describe learning and development in 5 key domains: (1) Executive functions; (2) Social and emotional learning; (3) Mathematical thinking; (4) Language and communication; and (5) Physical development. Each trajectory unpacks the domain into its composite subdomains and strands and sets out 4 indicators for each strand that describe how learning progresses. This report aims to demonstrate the strength of the evidence base for the trajectories, as well as to stimulate further exploration and reflection.