William Joseph Lynch (June 6, 1908 – August 9, 1976) was a United States federal judge.
Born in Chicago, Illinois, Lynch received an LL.B. from Loyola University Chicago School of Law in 1931. He was in private practice in Chicago, Illinois from 1931 to 1933. He was an Assistant state's attorney of Cook County, Illinois from 1933 to 1938. He was in private practice in Chicago, Illinois from 1938 to 1942. He was in the United States Navy during World War II, from 1942 to 1946. He was in private practice in Chicago, Illinois from 1946 to 1966. He was a member of the Illinois State Senate from 1950 to 1957. He was a Minority Leader, 1953, 1955 in 1957.
Lynch was a federal judge on the United States District Court for the Northern District of Illinois. Lynch was nominated by President Lyndon B. Johnson on January 19, 1966, to a seat vacated by Michael L. Igoe. He was confirmed by the United States Senate on March 4, 1966, and received his commission on March 7, 1966. Lynch served in that capacity until August 9, 1976, due to his death.
He died in Chicago, Illinois.