| Bob Barnes | |
| Position: | Pitcher |
| Bats: | Left |
| Throws: | Left |
| Birth Date: | 6 January 1902 |
| Birth Place: | Washburn, Illinois, U.S. |
| Death Place: | Peoria, Illinois, U.S. |
| Debutleague: | MLB |
| Debutdate: | July 8 |
| Debutyear: | 1924 |
| Debutteam: | Chicago White Sox |
| Finalleague: | MLB |
| Finaldate: | July 10 |
| Finalyear: | 1924 |
| Finalteam: | Chicago White Sox |
| Statleague: | MLB |
| Stat1label: | Win–loss record |
| Stat1value: | 0–0 |
| Stat2label: | Earned run average |
| Stat2value: | 19.29 |
| Stat3label: | Strikeouts |
| Stat3value: | 1 |
| Teams: | |
Robert Avery "Lefty" Barnes (January 6, 1902 – December 8, 1993) was an American Major League Baseball pitcher who played in two games for the Chicago White Sox in .