The 89th United States Congress was a meeting of the legislative branch of the United States federal government, composed of the United States Senate and the United States House of Representatives. It met in Washington, D.C., from January 3, 1965, to January 3, 1967, during the second and third years of Lyndon B. Johnson's presidency. The apportionment of seats in the House of Representatives was based on the 1960 United States census.

The Voting Rights Act of 1965 is a landmark piece of federal legislation in the United States that prohibits racial discrimination in voting. It was signed into law by President Lyndon B. Johnson during the height of the civil rights movement on August 6, 1965, and Congress later amended the Act five times to expand its protections. Designed to enforce the voting rights protected by the Fourteenth and Fifteenth Amendments to the United States Constitution, the Act sought to secure the right to vote for racial minorities throughout the country, especially in the South. According to the U.S. Department of Justice, the Act is considered to be the most effective piece of federal civil rights legislation ever enacted in the country. The National Archives and Records Administration stated: "The Voting Rights Act of 1965 was the most significant statutory change in the relationship between the federal and state governments in the area of voting since the Reconstruction period following the Civil War".