| Steve Mesner | |
| Position: | Third baseman |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 13 January 1918 |
| Birth Place: | Los Angeles, California |
| Death Place: | San Diego, California |
| Debutleague: | MLB |
| Debutdate: | September 23 |
| Debutyear: | 1938 |
| Debutteam: | Chicago Cubs |
| Finalleague: | MLB |
| Finaldate: | September 30 |
| Finalyear: | 1945 |
| Finalteam: | Cincinnati Reds |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .252 |
| Stat2label: | Home runs |
| Stat2value: | 2 |
| Stat3label: | Runs batted in |
| Stat3value: | 167 |
| Teams: | |
Stephen Mathias Mesner (January 13, 1918 – April 6, 1981) was a professional baseball player who was a third baseman in the Major Leagues at various times between 1938 and 1945. He played for the Chicago Cubs, St. Louis Cardinals, and Cincinnati Reds. He was also a long-time player in the minor leagues, cracking the lineup of the Los Angeles Angels of the Pacific Coast League at age 16 in 1934, and attaining starting status the following year. Mesner amassed 2,965 base hits in 21 seasons between the majors and minors.