The 1938 United States Senate election in Oklahoma took place on November 8, 1938. Incumbent Democratic Senator Elmer Thomas ran for re-election to a third term. He faced a spirited challenge in the Democratic primary from Congressman Gomer Smith and Governor E. W. Marland, but won the nomination with a slim plurality. In the general election, Thomas faced former State Senator Harry O. Glasser, the Republican nominee. Despite the nationwide trend favoring Republicans, Thomas overwhelmingly won re-election.
Democratic primary
Candidates
Elmer Thomas, incumbent U.S. Senator
Gomer Smith, U.S. Congressman from Oklahoma's 5th congressional district, 1932 Democratic candidate for the U.S. Senate E. W. Marland, Governor of Oklahoma Charles Francis Smith
Results
Republican primary
Candidates
Harry O. Glasser, former State Senator
James D. Davidson, real estate salesman
William Oliver Cromwell, former Oklahoma Attorney General, 1914 Progressive nominee for the U.S. Senate Wilfred Marion Leise