| Harry Mahnken | |
| Birth Date: | 15 July 1903 |
| Birth Place: | Brooklyn, New York, U.S. |
| Player Sport1: | Football |
| Player Team2: | Springfield |
| Player Sport3: | Baseball |
| Player Years4: | 1925–1927 |
| Player Team4: | Springfield |
| Player Years5: | 1927 |
| Player Team5: | Springfield Ponies |
| Player Years6: | 1927 |
| Player Team6: | Lawrence Merry Macks |
| Player Positions: | First baseman (baseball) |
| Coach Sport1: | Football |
| Coach Years2: | 1943–1944 |
| Coach Team2: | Princeton |
Harry Arthur Mahnken (July 15, 1903 – February 27, 1995) was an American college football coach. He served as the head football coach at Princeton University from 1943 to 1944, compiling a record of 2–8. A native of Brooklyn, Mahnken attended Springfield College in Springfield, Massachusetts, where he played football and baseball.[1]