The Diocese of Bayombong (Lat: Dioecesis Bayombongensis; formerly known as Praelatura Territorialis Bayombongensis) is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church in the Philippines.

Erected on November 7, 1966, through the apostolic constitution Patris Instar as the Territorial Prelature of Bayombong,[2] the said prelature was elevated to a diocese in November 1982 by Pope John Paul II through apostolic constitution Cum Decessores Nostri Romani Pontifices.

[3][4] The diocese is a suffragan of the Archdiocese of Tuguegarao.

After the resignation of Bishop Ramon Villena in 2016, Pope Francis appointed Sofronio Aguirre Bancud, SSS, DD, Bishop of Cabanatuan as Apostolic Administrator.

On May 24, 2018, the Pope appointed Jose Elmer I. Mangalinao, DD, Auxiliary Bishop of Lingayen-Dagupan, as the third Bishop of the Diocese of Bayombong.