Following a high-quality early care and pre-K experience, the kindergarten-through-third-grade years set the foundation upon which future learning builds; and strengthening this continuum creates opportunities for later success. Key components of a quality experience in K-3 include school readiness and transitions, kindergarten requirements, educator quality, prevention, intervention and assessments, and social and emotional learning and mental health. Education Commission of the States researched the policies and regulations that guide these key components in all 50 states to provide this comprehensive resource and many others. The data in this document show that at least 23 states and the District of Columbia have policies in place to guide the pre-K to kindergarten transition process. There are variations in which entities must be involved in guiding this transition process; states have alternately created requirements for state education agencies, state boards of education, school districts, district boards of education, county-based teams, individual preschool and kindergarten programs, and chief state school officers.