1920 United States Senate election in Iowa

The 1920 United States Senate election in Iowa was held on November 2, 1920. Incumbent Senator Albert B. Cummins was re-elected to a third term in office, defeating challenges from Smith W. Brookhart in the Republican primary and Claude R. Porter in the general election.

• Smith W. Brookhart, World War I veteran and marksman
• Albert B. Cummins, incumbent Senator since 1908

Albert B. Cummins was a progressive senator from an earlier generation who distrusted both corporate interests and trade unions. Brookhart campaigned against railroad regulations Cummins had co-authored, the Esch–Cummins Act, which Brookhart claimed did too little to wrest ownership and control of railroads away from Wall Street interests. Brookhart attempted to register rank-and-file blue-collar workers as Republicans so that they could vote for him in the primary, which prompted Cummins to associate Brookhart with radical workers movements such as "the Socialists, reds and Industrial Workers of the World." Cummins was sidelined by illness in the weeks leading up to the primary but defeated Brookhart.

• Claude Porter, former State Senator from Centerville

• H. W. Cowles (Farmer–Labor)
• Albert B. Cummins, incumbent Senator since 1908 (Republican)
• Arthur S. Dowler (Socialist Labor)
• Claude Porter, former State Senator from Centerville (Democratic)

• 1920 United States Senate elections