1940 United States Senate election in Washington

The 1940 United States Senate election in Washington was held on November 5, 1940. Incumbent Democrat Lewis Schwellenbach did not run for a second term in office. He was succeeded by Democratic U.S. Representative Monrad C. Wallgren, who defeated Republican Stephen Foster Chadwick for the open seat.

Democratic

 * Frank T. Bell, former Commissioner of Fish and Fisheries, former Treasurer of Grant County, and businessman
 * Harry C. Huse
 * Donald B. Miller, State Representative, and businessman
 * Roy B. Misener, King County Assessor
 * Robert Lee Smith
 * Monrad Wallgren, U.S. Representative from Everett

Republican

 * Stephen Fowler Chadwick, son of Stephen J. Chadwick, and candidate for Representative from Washington in 1926
 * Ewing D. Colvin, former Prosecutor of King County, and Washington State Bar Association official
 * Howard E. Foster
 * Eric Johnston, businessman, and former Marine
 * Robert Prior