Since their introduction in the early 1990s, charter schools, which provide a hybrid educational form that combines public funding with many of the educational policy freedoms that attend private schools, have experienced growing popularity across the country. As their numbers continue to increase, funding for charter schools has become more of a concern. Statistics indicate that charter school funding, which derives from federal, state, and local sources, has not kept pace with the funding accorded traditional public school systems. This disparity has led some charter school constituents to consider equal protection challenges against these allegedly discriminatory funding regimes. The Supreme Court's 1973 decision in San Antonio Independent School District v. Rodriguez, however, has led many to conclude that the doors to the federal courthouse remain closed to equal protection litigants protesting inequities in school funding. The author begins by presenting background information on federal equal protection jurisprudence, the charter school concept, and the purported discrepancies in charter school funding. After discussing the continued viability of education as a fundamental right, he then considers the Court's Rodriguez decision in light of its subsequent rulings in Papasan v. Allain and Plyler v. Doe. Following an examination of charter school characteristics relevant to charter school equal protection challenges, the author contends that Papasan and, to a lesser extent, Plyler, present alternative avenues that would allow charter school plaintiffs to circumvent the Rodriguez barriers. He concludes that, ironically, charter school plaintiffs have the strongest chance to raise a successful federal equal protection claim by confronting the government's lowest hurdle: rational basis review. Under what he terms the "Papasan exception," Rubio contends that Rodriguez explicitly made itself inapplicable to a state's decision to divide resources unequally among its school districts and that, therefore, federal equal protection challenges remain available to charter school litigants who have inexplicably been denied access to entire categories of state funds.