Demetrios J. Marantis (born May 28, 1968) is an American lawyer and government official. He served as the acting United States Trade Representative (USTR) from March 15, 2013 until May 23, 2013. He served as the Deputy Trade Representative under Ron Kirk, and became the acting Trade Representative when Kirk resigned in March 2013.Marantis attended Harrison High School in Harrison, New York. He received a Bachelor of Arts in public and international affairs from Princeton University in 1990.