There is a growing body of evidence that coaching early childhood educators leads to improved instruction, and influences children's learning outcomes. Despite this, consensus is lacking about how coaching as a form of professional development is defined, what it should involve, and how much should be offered. This paper outlines the findings of a review of English-language empirical research literature on successful coaching interventions in early childhood education. It identifies critical features of successful coaching, as well as areas warranting further exploration and implications for practice. The comprehensive review, drawing from methods of systematic review and rapid appraisal, confirmed that observation, feedback, goal-setting and reflection are common elements of successful coaching programmes. Analysis of the structures and processes of successful coaching interventions identified that in order to bring about practice change, the amount and content of coaching should be aligned with educators' characteristics, skills and contexts. It further confirmed that effective coaching should allow educators opportunities to apply new skills, and support them to reflect on their practice and set self-directed goals. Further research is needed to explore not just what works, but why and in what context.