Family engagement has long been emphasized as part of developmentally appropriate practice for programs serving young children and their families. It is a hallmark of high-quality early childhood programs. Family engagement is increasingly being seen as a powerful lever for increasing and sustaining the positive impact of early education programs on child learning and development. Although there is agreement that family engagement includes a number of dimensions, defining and measuring family engagement continues to be a challenge in early childhood education. These dimensions include aspects of teacher (or provider) and family relationships, as well as program-level factors that support family engagement. As a result, ensuring that programs effectively engage families, especially in the context of diversity or high social risk, is a challenge in quality improvement. This Brief considers these issues within the context of ongoing analyses examining program performance on NAEYC Accreditation standards. (author abstract)