Roman Catholic Diocese of Thunder Bay

Diocese of Thunder Bay Dioecesis Sinus Tonitralis
St. Patrick's Cathedral in Thunder Bay
Coat of Arms
Location
Country	Canada
Territory	Northern Ontario
Ecclesiastical province	Archdiocese of Toronto
Metropolitan	Thunder Bay, Ontario
Coordinates	48°22′56″N 89°14′58″W / 48.38222°N 89.24944°W / 48.38222; -89.24944
Statistics
Population - Total - Catholics	(as of 2022) 290,142 89,000 (est.)
Information
Denomination	Roman Catholic
Rite	Roman Rite
Established	April 29, 1952
Cathedral	St. Patrick's Cathedral
Patron saint	St. Patrick
Secular priests	28 31 Permanent Deacons
Current leadership
Pope	Francis
Bishop	Alan Campeau
Metropolitan Archbishop	Frank Leo
Bishops emeritus	Frederick Joseph Colli
Website
dotb.ca

The Roman Catholic Diocese of Thunder Bay (Latin: Dioecesis Sinus Tonitralis) is a Latin suffragan in the ecclesiastical province of the Metropolitan Archdiocese of Toronto, in Ontario, Canada.

Its cathedral episcopal see is St. Patrick's Cathedral, dedicated to St. Patrick, in Thunder Bay, Ontario.