| William W. Knox | |
| Office: | Judge of the United States District Court for the Western District of Pennsylvania |
| Term Start: | October 14, 1970 |
| Term End: | August 30, 1981 |
| Appointer: | Richard Nixon |
| Predecessor: | Seat established by 84 Stat. 294 |
| Successor: | Carol Los Mansmann |
| Birth Name: | William W. Knox |
| Birth Date: | 18 June 1911 |
| Birth Place: | Erie, Pennsylvania |
| Death Place: | Erie, Pennsylvania |
| Education: | University of Michigan (A.B., J.D.) |
William W. Knox (June 18, 1911 – August 30, 1981) was a United States district judge of the United States District Court for the Western District of Pennsylvania.
Born in Erie, Pennsylvania, Knox received an Artium Baccalaureus degree from the University of Michigan in 1932 and a Juris Doctor from the University of Michigan Law School in 1935. He was in private practice in Erie from 1935 to 1970.
On September 28, 1970, Knox was nominated by President Richard Nixon to a new seat on the United States District Court for the Western District of Pennsylvania created by 84 Stat. 294. He was confirmed by the United States Senate on October 8, 1970, and received his commission on October 14, 1970. Knox served in that capacity until his death, on August 30, 1981, in Erie.