Gaines v. Thompson was a United States Supreme Court case that dealt with the issue of racial segregation in public education. The case was brought by a black student, Lloyd Gaines, who was denied admission to the University of Missouri Law School due to its policy of racial segregation. Gaines argued that the policy violated the Equal Protection Clause of the Fourteenth Amendment. The Supreme Court agreed with Gaines and ruled that the University of Missouri must admit him or provide an equal educational opportunity elsewhere. The ruling was a landmark decision in the fight for racial equality in education and set a precedent for future cases. The decision was also significant in that it was the first time the Supreme Court had ruled on the issue of racial segregation in public education. The ruling in Gaines v. Thompson was a major step forward in the fight for racial equality in the United States.

In Gaines v. Thompson, the Supreme Court was asked to decide whether a state law that required African American students to attend separate schools from white students violated the Equal Protection Clause of the Fourteenth Amendment. The majority opinion held that it did not violate this clause because states had broad power over educational policy and could choose how best to provide education for its citizens. However, in his dissent Justice Field argued that such laws were unconstitutional as they denied African Americans equal protection under the law by creating an unequal system of education based on race alone. He further argued that these laws created a stigma against African Americans which would have long-term effects on their ability to participate fully in society and enjoy all rights afforded them by both federal and state constitutions.