William Lacy Clay Sr. (born April 30, 1931) is an American politician from Missouri.

Clay served 105 days in jail for participating in a civil rights demonstration in 1963.

Prior to entering Congress, Clay held jobs first as a real-estate broker and later as a labor coordinator.

[2][3] The Clay family were parishioners at the predominantly black St. Nicholas Roman Catholic Church in St. Louis.

From 1991 until the Democrats lost control of Congress in 1995, Clay chaired the House Committee on the Post Office and Civil Service.