| Election Name: | 1934 Democratic Senate primary election in Mississippi |
| Country: | Mississippi |
| Flag Image: | Flag of Mississippi (1894-1996).svg |
| Type: | Presidential |
| Ongoing: | no |
| Previous Election: | 1928 United States Senate election in Mississippi |
| Previous Year: | 1928 |
| Next Election: | 1940 United States Senate election in Mississippi |
| Next Year: | 1940 |
| Election Date: | September 18, 1934 |
| Image1: | File:Theodore Bilbo (cropped).jpg |
| Nominee1: | Theodore Bilbo |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 101,702 |
| Percentage1: | 51.81% |
| Nominee2: | Hubert Stephens |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 94,587 |
| Percentage2: | 48.19% |
| Map Size: | 150px |
| U.S. Senator | |
| Before Election: | Hubert Stephens |
| Before Party: | Democratic Party (United States) |
| After Election: | Theodore Bilbo |
| After Party: | Democratic Party (United States) |
The 1934 United States Senate election in Mississippi was held on November 6, 1934. Incumbent Senator Hubert Stephens ran for re-election to a third term, but was defeated by Governor Theodore Bilbo in a close run-off election.
On August 28, Stephens won the Democratic primary over Bilbo and Meridian Congressman Ross Collins in a close three-way race. Since no candidate received a majority of the vote, the election proceeded to a run-off between Stephens and Bilbo. On September 18, Bilbo won the run-off by just 7,115 votes.
Bilbo won the November general election without an opponent.