The 20th United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1827, to March 4, 1829, during the third and fourth years of John Quincy Adams's presidency. The apportionment of seats in the House of Representatives was based on the 1820 United States census. Both chambers had a Jacksonian majority.

Andrew Stevenson was an American politician, lawyer and diplomat. He represented Richmond, Virginia in the Virginia House of Delegates and eventually became its speaker before being elected to the United States House of Representatives; its members subsequently elected him their Speaker. Stevenson also served in the Jackson administration for four years as the U.S. ambassador to the United Kingdom before retiring to his slave plantation in Albemarle County. He also served on the board of visitors of the University of Virginia and briefly as its rector before his death.