William J. Lederer (December 14, 1924 – January 20, 2008) was an American politician and judge.
Born in Philadelphia, Pennsylvania on December 14, 1924, Lederer served as a staff sergeant and Information and Education Director with the United States Army during World War II (1943, North Africa: 1944-1946, Burma, India, and China).
After graduating from North East High School in 1946, he earned his Bachelor of Science degree in political science from La Salle University in 1950 and his Bachelor of Law degree (LL.B) from Temple University Beasley School of Law in 1953.
A visiting lecturer at Temple University's Law School from 1957 through 1977, he also served as general counsel to Philadelphia County's Office of the Register of Wills from 1958 to 1963, and as the chair of the Veterans Commission of Philadelphia from 1958 to 1964.
His father Miles, his brother Raymond, and his wife Marie also served in the Pennsylvania General Assembly.