Robert Emmet Lighthizer (born October 11, 1947) is an American lawyer. He was the 18th United States Trade Representative from May 15, 2017 to January 20, 2021.

Lighthizer is a partner with the law firm of Skadden, Arps, Slate, Meagher & Flom, where he works to gain access to foreign markets on behalf of U.S. corporations. In the 1980s, he served as deputy trade representative during President Ronald Reagan's administration.