This synthesis brings together and analyses research evidence about professional development for teachers/educators in the early childhood education sector. The focus is on evidence about features of quality professional development related to children's learning opportunities, experiences and outcomes (social and dispositional as well as cognitive). Attention is paid to contextual issues, and the influences of culture, ethnicity and language. There is an emphasis on evidence related to the characteristics and impact of provision of effective professional development for learning opportunities of Maori and Pasifika children, and of children in low socio-economic circumstances. The synthesis analyses implications for strategic and operational policy initiatives and identifies questions and gaps where further research is needed. (author abstract)