Systematic and ongoing assessment of children's skills and progress is at the heart of developmentally appropriate practice in early childhood classrooms. Careful assessment enables teachers to know the children with whom they work. Effective early childhood practice focuses on the needs of the whole child, so child assessment must similarly focus on all domains of development. Social development is one such domain, and encompasses many aspects of children's behavior. Teachers continually observe children in context to better understand their social competence. This article offers guidelines for conducting appropriate assessment, identifies specific elements of children's social competence, and suggests strategies for using assessment information to support children's social skill development. (Contains 3 figures.)