The Roman Catholic Diocese of Montego Bay (Latin: Dioecesis Sinus Sereni) is a Latin suffragan diocese of the Roman Catholic Church located on the northwest part of the island of Jamaica (Greater Antilles), in the Caribbean ecclesiastical province of the Metropolitan Archdiocese of Kingston (which covers all Jamaica, the Cayman Islands and Belize), yet depends on the missionary Roman Congregation for the Evangelization of Peoples.

Its episcopal see is the Most Blessed Sacrament Cathedral, in Montego Bay, Saint James (civil) parish.

Pope Francis appointed Burchell Alexander McPherson of the Archdiocese of Kingston the third Bishop of Montego Bay on April 11, 2013.

[1] The diocese of Montego Bay is made up of five administrative parishes: St. James, Trelawny, St. Ann, Westmoreland and Hanover.

Many parishes rely on missionary priests to aid in the celebration of Mass and the sacraments.