Enguerrand IV, Lord of Coucy (c. 1236 – 1311) was the younger brother and successor of Raoul II, Lord of Coucy, serving as the powerful Sire de Coucy from his brother's death in 1250 until his own in 1311.
Enguerrand IV succeeded to the large fief established by his father, Enguerrand the Great, due to his elder brother's death on Crusade. His rule was notable for his crimes and cruelty, leading in one instance to his imprisonment by Louis IX. Setting important medieval legal precedent, the King refused to allow him trial by combat for the hanging of three squires found on his land. In the end, Enguerrand escaped with a fine, and through his wealth remained important to the King, lending him 15,000 livres in 1265 to purchase a piece of the True Cross. He was married twice, but had no children, and was succeeded by the second son of his sister, Alix, who became Enguerrand V.