| William K. Martin | |
| Birth Date: | 1867 |
| Death Date: | (aged 81) |
| Death Place: | Crawfordsville, Indiana, U.S. |
| Player Sport1: | Football |
| Player Years2: | 1886 |
| Player Team2: | Wabash |
| Player Positions: | Quarterback |
| Coach Sport1: | Football |
| Coach Years2: | 1887 |
| Coach Team2: | Wabash |
| Coach Sport3: | Baseball |
| Coach Years4: | 1889–1892 |
| Coach Team4: | Wabash |
| Overall Record: | 0–1 (football) 19–10 (baseball) |
William K. "Uncle Billy" Martin (1867 – July 10, 1949) was an American college football and college baseball coach. He was the third head football coach at Wabash College in Crawfordsville, Indiana, serving for one season, in 1887 season, and compiling a record of 0–1.[1] Martin was also the head baseball coach at Wabash from 1889 to 1892, tallying a mark of 19–10. Martin died on July 10, 1949, at his home in Crawfordsville.[2] [3]