The 24th Amendment to the United States Constitution was ratified on January 23, 1964, and it prohibits both Congress and the states from conditioning the right to vote in federal elections on payment of a poll tax or other types of tax. The amendment was proposed by Congress to the states on August 27, 1962, and it was ratified by the states on January 23, 1964. When the 24th Amendment was ratified in 1964, five states still retained a poll tax: Alabama, Arkansas, Mississippi, Texas, and Virginia. The amendment prohibited requiring a poll tax for voters in federal elections. However, it was not until 1966 that the U.S. Supreme Court ruled 6–3 in Harper v. Virginia Board of Elections that poll taxes for any level of elections were unconstitutional.

The 24th Amendment was adopted as a response to policies adopted in various Southern states after the ending of post-Civil War Reconstruction (1865–77) to limit the political participation of African Americans. Such policies were bolstered by the 1937 U.S. Supreme Court decision in Breedlove v. Suttles, which upheld a Georgia poll tax. During the civil rights era of the 1950s, particularly following the Brown v. Board of Education decision in 1954, such policies increasingly were seen as barriers to voting rights, particularly for African Americans and the poor. Thus, the Twenty-fourth Amendment was proposed and ratified to eliminate an economic instrument that was used to limit voter participation.