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 resource and many others. The data in this document show that at least 28 states have statutes or regulations outlining teacher-to student ratios, ranging from a 1-15 ratio to a 1-25 ratio, with some states providing districts with oversight. An additional 10 states outline maximum class size, with the maximum class size for kindergarten of 33 students. Several states combine these in statute or regulation. Five states include laws that dictate funding must be used to lower teacher-to-student ratios when funds are available. Fourteen states and Washington, D.C., have no statutes or regulations regarding this issue.