Jean Marc Christ Koumadje (born July 7, 1996) is a Chadian professional basketball player for Avtodor Saratov in Russia.
Koumadje played college basketball at Florida State. During his senior season at FSU, Koumadje averaged 6.6 points per game, 5.6 rebounds per game, 1.4 blocks per game, and 15.5 minutes played per game. After his college career, Koumadje signed with the Philadelphia 76ers and was added to their training camp roster, then assigned to their G League affiliate. He was named NBA G League Defensive Player of the Year last season with the Delaware Blue Coats.