Bishop Ireneo "Ali" Amantillo (10 December 1934 - 11 October 2018) was a Filipino Roman Catholic bishop and was the first bishop of the Roman Catholic Diocese of Tandag located in Tandag City, Surigao del Sur.
Amantillo was born in the Philippines and was ordained to the priesthood in 1962. He served as titular bishop of Girius and was auxiliary bishop of the Roman Catholic Archdiocese of Cagayan de Oro, Philippines from 1976 to 1978. He was appointed by Pope John Paul I on September 6, 1978, and was installed as the first bishop of the Roman Catholic Diocese of Tandag on November 7, 1978.[1] He reigned from 1978 until his retirement in 2001.[2] He died on October 11, 2018, due to prostate cancer.