Bầu cử Thượng viện Hoa Kỳ tại Iowa năm 2020

The 2020 United States Senate election in Iowa was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Iowa, concurrently with the 2020 U.S. presidential election, as well as other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections. Primaries were held on June 2. Incumbent Republican Senator Joni Ernst won re-election to a second term, defeating Democratic nominee Theresa Greenfield.

Most experts and pollsters considered this race and the concurrent presidential race as a tossup due to incumbent president Donald Trump's low approval ratings and Ernst's own popularity dropping in polls, partly due to a viral moment in a debate where she did not know the break-even price for soybeans. Despite this, Ernst was reelected by a larger-than-expected 6.6 points, while Trump simultaneously won the state with a bigger yet similarly unexpected margin of victory. Ernst carried an overwhelming majority of the state's counties including many rural ones, while Greenfield carried only eight counties: Polk, Linn, Scott, Johnson, Black Hawk, Story, Cerro Gordo and Jefferson.