William Lacy Clay Jr. (son of William Lacy Clay, Sr.) is a Representative from Missouri. He was born in St. Louis, Missouri on July 27, 1956.
He received his B.A. from the University of Maryland in 1983. He was a member of the Missouri state house of representatives from 1983-1991, and was a member of the Missouri state senate from 1991-2001.
He was elected as a Democrat to the One Hundred Seventh and to the eight succeeding Congresses (January 3, 2001-present).