The Immigration and Nationality Act of 1965, also known as the Hart–Celler Act and more recently as the 1965 Immigration Act, is a landmark federal law passed by the 89th United States Congress and signed into law by President Lyndon B. Johnson. The law abolished the National Origins Formula, which had been the basis of U.S. immigration policy since the 1920s. The act formally removed de facto discrimination against Southern and Eastern Europeans as well as Asians, in addition to other non-Western and Northern European ethnicities from the immigration policy of the United States.

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.