| Birth Date: | 6 December 1910 |
| Birth Place: | Aurora, Illinois, U.S. |
| Team: | Purdue Boilermakers |
| Position1: | Running back |
| College: | Purdue |
| Playing Years1: | 1933 |
| Playing Team1: | Boston Redskins |
| Playing Years2: | 1934 |
| Playing Team2: | Chicago Cardinals |
| Career Highlights: |
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| Nfl: | HOR533934 |
| Databasefootball: | HORSTROY01 |
Roy Joseph Horstmann (December 6, 1910 - January 23, 1998) was an American football running back in the National Football League (NFL) for the Boston Redskins and Chicago Cardinals. He played college football at Purdue University. While at Purdue, Horstmann was a brother at Theta Tau fraternity (Roll Number: Phi 097).