The Bishop of Trebinje-Mrkan is the head of the Roman Catholic Diocese of Trebinje-Mrkan, who is responsible for looking after its spiritual and administrative needs.
The seat is vacant since 1819, and the bishops of Mostar-Duvno serve as the apostolic administrators since 1890.
The Diocese of Trebinje-Mrkan is part of the ecclesiastical province of Vrhbosna and thus is a suffragan of that archdiocese.
[1]: 114 The current apostolic administrator is Petar Palić since 2020.