Stephen Gerald Breyer is an American lawyer and jurist who served as an associate justice of the U.S. Supreme Court from 1994 until his retirement in 2022. He was nominated by President Bill Clinton, and replaced retiring justice Harry Blackmun. Breyer was generally associated with the liberal wing of the Court. He is now the Byrne Professor of Administrative Law and Process at Harvard Law School.

An associate justice of the Supreme Court of the United States is a justice of the Supreme Court of the United States, other than the chief justice of the United States. The number of associate justices is eight, as set by the Judiciary Act of 1869.