John de Courcy (also John de Courci) 1160–1219) is an Anglo-Norman knight who arrives in Ireland in 1176.

From then until his expulsion in 1204, he conquers a considerable territory, endows religious establishments, builds abbeys for both the Benedictines and the Cistercians and builds strongholds at Dundrum Castle in County Down and Carrickfergus Castle in County Antrim.