The 1920 United States Senate elections were elections for the United States Senate that coincided with the presidential election of Warren G. Harding. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies. Democrat Woodrow Wilson's unpopularity allowed Republicans to win races across the country, winning ten seats from the Democrats and providing them with an overwhelming 59-to-37 majority. The Republican landslide was so vast that Democrats lost over half of the seats that were contested this year and failed to win a single race outside the South.

Thomas Edward Watson was an American Populist and white supremacist politician, attorney, newspaper editor, and writer from Georgia. In the 1890s Watson championed poor farmers as a leader of the Populist Party, articulating an agrarian political viewpoint while attacking business, bankers, railroads, Democratic President Grover Cleveland, and the Democratic Party. He was the nominee for vice president with Democrat William Jennings Bryan in 1896 on the Populist ticket.