| Walt Marbet | |
| Position: | Pitcher |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 13 September 1890 |
| Birth Place: | Plymouth County, Iowa |
| Death Place: | Hohenwald, Tennessee |
| Debutleague: | MLB |
| Debutdate: | June 17 |
| Debutteam: | St. Louis Cardinals |
| Finalleague: | MLB |
| Finaldate: | June 25 |
| Finalteam: | St. Louis Cardinals |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0–1 |
| Stat2label: | Earned run average |
| Stat2value: | 16.20 |
| Stat3label: | Strikeout(s) |
| Stat3value: | 1 |
| Teams: | |
Walter William Marbet (September 13, 1890 – September 24, 1956) was a Major League Baseball pitcher who played with the St. Louis Cardinals in .