In this article, we aim to chart a path for a new generation of early care and education (ECE) quality assessments that accurately and equitably capture key inputs to the social–emotional well-being of the diverse population of young children in ECE classrooms in the United States. We zero in on four promising, socially supportive features of center-based ECE settings that are actionable for research, policy, and practice: teachers' classroom behavior-management strategies, their scaffolding of peer interactions, aspects of their own well-being that shape their capacities to support children's social–emotional development, and indicators of bias-free and culturally responsive ECE environments. (author abstract)