| Fred Ostendorf | |
| Position: | Pitcher |
| Birth Date: | 5 August 1892 |
| Birth Place: | Baltimore, Maryland, US |
| Death Place: | Kecoughtan, Virginia, US |
| Bats: | Left |
| Throws: | Left |
| Debutleague: | MLB |
| Debutdate: | July 16 |
| Debutteam: | Indianapolis Hoosiers |
| Finalleague: | MLB |
| Finaldate: | July 16 |
| Finalteam: | Indianapolis Hoosiers |
| Statleague: | MLB |
| Stat1label: | Pitching record |
| Stat1value: | 0-0 |
| Stat2label: | Strikeouts |
| Stat2value: | 0 |
| Stat3label: | Earned run average |
| Stat3value: | 22.50 |
Frederick K. Ostendorf (August 5, 1892 - March 2, 1965) was an American professional baseball player who played in one game for the Indianapolis Hoosiers of the Federal League during the season.
He was born in Baltimore, Maryland and died in Kecoughtan, Virginia at the age of 72.