The funding of public elementary and secondary schools in the United States involves a combination of local, state, and federal government revenues. State and local governments generally provide over 90% of the revenue available for public elementary and secondary education on an annual basis, with the federal government providing the remainder. As such, there is consistent congressional interest in understanding how the majority of available funds are provided to local educational agencies (LEAs) and, ultimately, to public schools. This report intends to provide context for consideration of the comparatively small but important role of the federal assistance programs in financing public education, discuss some of the ways that state and local finance policies and practices intersect with federal involvement, and explain selected key concepts in this field. The report provides a basic overview of the mechanisms used by states and LEAs to fund public education and an introduction to core school finance concepts. It then focuses on state school finance programs, the varieties of policies under which states provide funds to LEAs, and the local units of government that administer public K-12 education. The next section considers LEA programs to finance individual public schools. The report concludes with a review of recent efforts to collect and report data on the level of expenditures per pupil at individual public schools within LEAs, a topic that has garnered increasing interest among policymakers in recent years.