| William Muir | |
| Birth Date: | 1 February 1895 |
| Birth Place: | Brock, Nebraska, U.S. |
| Death Place: | Howard County, Missouri, U.S. |
| Player Sport1: | Football |
| Player Years2: | 1915–1916 |
| Player Team2: | Missouri |
| Player Positions: | Guard[1] |
| Coach Sport1: | Football |
| Coach Years2: | 1923–1925 |
| Coach Team2: | Northern Illinois State |
| Coach Sport3: | Basketball |
| Coach Years4: | 1923–1926 |
| Coach Team4: | Northern Illinois State |
| Coach Sport5: | Baseball |
| Coach Years6: | 1924–1926 |
| Coach Team6: | Northern Illinois State |
| Admin Years1: | 1923–1926 |
| Admin Team1: | Northern Illinois State |
| Overall Record: | 11–9–3 (football) 24–6 (baseball) |
William George Muir (February 1, 1895 – January 5, 1967) was an American football, basketball, and baseball coach.[2] [3] He served as the head football coach at Northern Illinois University from 1925 to 1925, compiling a record of 11–9–3. Muir was also the head basketball coach at Northern Illinois from 1923 to 1926 and the head baseball coach at the school from 1924 to 1926. He graduated from the University of Missouri and also attended coaching school at the University of Illinois. Prior to coming to Northern Illinois, he had taught and coached in Kansas, Texas, and in Decatur, Illinois.[4]