| Election Name: | 1938 United States Senate election in Oklahoma |
| Country: | Oklahoma |
| Flag Year: | 1925 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1932 United States Senate election in Oklahoma |
| Previous Year: | 1932 |
| Next Election: | 1944 United States Senate election in Oklahoma |
| Next Year: | 1944 |
| Election Date: | November 8, 1938 |
| Image1: | File:Oklahoma Senator. Washington, D.C., April 19, 1939 A new informal picture of Senator Elmer Thomas, Democrat of Oklahoma LCCN2016875466 (cropped).jpg |
| Nominee1: | Elmer Thomas |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 307,936 |
| Percentage1: | 65.37% |
| Nominee2: | Harry O. Glasser |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 159,734 |
| Percentage2: | 33.91% |
| Map Size: | 300px |
| U.S. Senator | |
| Before Election: | Elmer Thomas |
| Before Party: | Democratic Party (United States) |
| After Election: | Elmer Thomas |
| After Party: | Democratic Party (United States) |
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.