The Diocese of Iligan (Lat: Dioecesis Iliganensis) is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church in the Philippines, comprising 26 parishes in Iligan City and twelve municipalities located at the northern half of the province of Lanao del Norte.

Erected on February 17, 1971, as a territorial prelature out of the newly elevated Diocese of Ozamis, it was subdivided on November 20, 1976, to form the new Territorial Prelature of Marawi.

On November 15, 1982, the prelature nullius was elevated to a full diocese and is a suffragan first to the Archdiocese of Cagayan de Oro and then later to the Archdiocese of Ozamis after its elevation on January 24, 1983.

The current bishop is Jose Rapadas III, appointed in 2019.

Bishop Rapadas was a diocesan clergyman from the Diocese of Ipil in the province of Zamboanga Sibugay.