The 1920 United States Senate election in Wisconsin was held on November 2, 1920. Incumbent Senator Irvine Lenroot, who had been elected to complete the unexpired term of Paul O. Husting, was re-elected to a full term in office.

Irvine Luther Lenroot was an American attorney, jurist, and Republican Party politician from Wisconsin. He served as Speaker of the Wisconsin State Assembly from 1903 to 1907 and represented the state in the United States Congress from 1909 to 1927, first in the United States House of Representatives until 1918, and then in the United States Senate. After he lost the Republican nomination in 1926, Herbert Hoover nominated him to the United States Court of Customs and Patent Appeals.