Horne v. Flores, 557 U.S. 433 (2009), is a case in which the United States Supreme Court remanded the case to determine whether Arizona's general education funding budget supports Equal Educational Opportunities Act of 1974 (EEOA)-compliant English Language Learner (ELL) programming.

The case was brought in 1992 by English Language Learner (ELL) students against the state board of education and state superintendent on the grounds that the Nogales Unified School District had failed to teach the students English, which was vital to their success.

In 2000, after almost eight years of pretrial proceedings and settling of various claims, the federal district court in Arizona held that the state was violating the Equal Educational Opportunity Act because the amount of funding it allocated for the special needs of ELL students was arbitrary and not related to the actual funding needed to cover the costs of ELL instruction in the plaintiffs' school district.

The opinion held that in evaluating the actions of the state attention should focus on student outcomes rather than on spending and inputs to schools.

Justice Breyer argued that the lower courts did fairly consider every change in circumstances that the parties called to their attention, and that the majority opinion risks denying schoolchildren the English language instruction necessary to overcome language barriers that impede equal participation.