The Sustainable Development Goals (SDGs) offer a historic opportunity to implement large-scale interventions to promote Early Childhood Development (ECD). While the evidence base for the importance of ECD has grown, research is spread across sectors, populations, and settings, with diversity in scope and focus. This paper provides a comprehensive updated analysis of ECD interventions across five sectors: health, nutrition, education, child protection, and social protection. The review concludes that to make interventions successful, smarter, and sustainable, they need to be implemented as multi-sectoral intervention packages anchored in "nurturing care." The recommendations emphasize that intervention packages should be applied at developmentally appropriate times during the life-course, target multiple risks, and build on existing delivery platforms for feasibility of scale-up. While interventions will continue to improve with the growth of developmental science, the evidence is now strong that parents, caregivers, and families need to be supported in providing nurturing care and protection for young children to achieve their developmental potential. Nurturing care is defined as a stable environment that is sensitive to children's health and nutritional needs, with protection from threats, opportunities for early learning, and interactions that are responsive, emotionally supportive, and developmentally stimulating. It is supported by a range of social contexts, including home, parental work, child care, schooling, wider community, and policy influences. Nurturing care includes core functions such as caregiving behaviors, stimulation, responsiveness, and safety. The single most powerful context for nurturing care is the immediate home and care settings of young children, often provided by mothers, but also by fathers and other family members, as well as by child care services. The brain has evolved to be highly sensitive to nurturing care, which mediates the development of key brain regions and promotes developmental adaptations. These experiences have lifelong benefits, including increased ability to learn, greater achievement in school and later life, citizenship, involvement in community activities, and overall quality of life. The period of early development is one of enormous change and is characterized by a high degree of plasticity in brain organization. Advances in developmental science have also provided an understanding of the multiple and overlapping critical windows of time when development of specific capacities and abilities is most powerfully enhanced. The review identified 14 types of interventions that show benefit on multiple child outcomes, including child development, based on high-quality systematic reviews. These interventions include parenting support, social protection, care for the caregiver, and early learning opportunities. The review also highlights the importance of integrating nurturing care with sector-specific programmes to improve child development outcomes. The review suggests that multi-sectoral intervention packages that integrate nurturing care with sector-specific programmes can significantly improve child developmental outcomes. The review also emphasizes the importance of combining nurturing care with other interventions, such as parenting support and skills programmes, to improve interventions. The review concludes that nurturing care and protection can mediate risk factors in early childhood and that integrating nurturing care with sector-specific programmes is essential for improving child development outcomes.The Sustainable Development Goals (SDGs) offer a historic opportunity to implement large-scale interventions to promote Early Childhood Development (ECD). While the evidence base for the importance of ECD has grown, research is spread across sectors, populations, and settings, with diversity in scope and focus. This paper provides a comprehensive updated analysis of ECD interventions across five sectors: health, nutrition, education, child protection, and social protection. The review concludes that to make interventions successful, smarter, and sustainable, they need to be implemented as multi-sectoral intervention packages anchored in "nurturing care." The recommendations emphasize that intervention packages should be applied at developmentally appropriate times during the life-course, target multiple risks, and build on existing delivery platforms for feasibility of scale-up. While interventions will continue to improve with the growth of developmental science, the evidence is now strong that parents, caregivers, and families need to be supported in providing nurturing care and protection for young children to achieve their developmental potential. Nurturing care is defined as a stable environment that is sensitive to children's health and nutritional needs, with protection from threats, opportunities for early learning, and interactions that are responsive, emotionally supportive, and developmentally stimulating. It is supported by a range of social contexts, including home, parental work, child care, schooling, wider community, and policy influences. Nurturing care includes core functions such as caregiving behaviors, stimulation, responsiveness, and safety. The single most powerful context for nurturing care is the immediate home and care settings of young children, often provided by mothers, but also by fathers and other family members, as well as by child care services. The brain has evolved to be highly sensitive to nurturing care, which mediates the development of key brain regions and promotes developmental adaptations. These experiences have lifelong benefits, including increased ability to learn, greater achievement in school and later life, citizenship, involvement in community activities, and overall quality of life. The period of early development is one of enormous change and is characterized by a high degree of plasticity in brain organization. Advances in developmental science have also provided an understanding of the multiple and overlapping critical windows of time when development of specific capacities and abilities is most powerfully enhanced. The review identified 14 types of interventions that show benefit on multiple child outcomes, including child development, based on high-quality systematic reviews. These interventions include parenting support, social protection, care for the caregiver, and early learning opportunities. The review also highlights the importance of integrating nurturing care with sector-specific programmes to improve child development outcomes. The review suggests that multi-sectoral intervention packages that integrate nurturing care with sector-specific programmes can significantly improve child developmental outcomes. The review also emphasizes the importance of combining nurturing care with other interventions, such as parenting support and skills programmes, to improve interventions. The review concludes that nurturing care and protection can mediate risk factors in early childhood and that integrating nurturing care with sector-specific programmes is essential for improving child development outcomes.