| Election Name: | 1943 Mississippi Democratic gubernatorial primary runoff |
| Type: | presidential |
| Country: | Mississippi |
| Flag Image: | Flag of Mississippi (1894-1996).svg |
| Previous Election: | 1939 Mississippi gubernatorial election |
| Previous Year: | 1939 |
| Next Election: | 1947 Mississippi gubernatorial election |
| Next Year: | 1947 |
| Ongoing: | no |
| Election Date: | November 2, 1943 |
| Nominee1: | Thomas L. Bailey |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 143,153 |
| Percentage1: | 53.21% |
| Nominee2: | Martin S. Conner |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 125,882 |
| Percentage2: | 46.79% |
| Map Size: | 250px |
| Governor | |
| Before Election: | Paul B. Johnson Sr. |
| Before Party: | Democratic Party (United States) |
| After Election: | Thomas L. Bailey |
| After Party: | Democratic Party (United States) |
The 1943 Mississippi gubernatorial election took place on November 2, 1943 to elect the Governor of Mississippi. Incumbent Democrat Paul B. Johnson Sr. was term-limited, and could not run for reelection to a second term (he died less than two months after the election was held). As was common at the time, the Democratic candidate ran unopposed in the general election so therefore the Democratic primary was the real contest, and winning the primary was considered tantamount to election.
No candidate received a majority in the Democratic primary, which featured 4 contenders, so a runoff was held between the top two candidates. The runoff election was won by former state representative Thomas L. Bailey, who defeated former Governor Martin S. Conner.
In the general election, Bailey ran unopposed.