| Jurisdiction: | Diocese |
| Saint John in New Brunswick | |
| Latin: | Dioecesis Sancti Ioannis Canadensis |
| Local: | Diocèse de Saint-Jean au Nouveau-Brunswick |
| Coat: | Coat of Arms of the Roman Catholic Diocese of St. John's, New Brunswick.svg |
| Coat Size: | 180px |
| Coat Caption: | Coat of arms |
| Country: | Canada |
| Province: | Moncton |
| Coordinates: | 45.28°N -66.0568°W |
| Area Km2: | 60,000 |
| Population: | 331,800 |
| Population As Of: | 2020 |
| Catholics: | 132,600 |
| Catholics Percent: | 40.0 |
| Parishes: | 58 |
| Denomination: | Roman Catholic |
| Rite: | Roman Rite |
| Cathedral: | Cathedral of the Immaculate Conception |
| Patron Title: | Patron saints |
| Patron: | Our Lady of the Immaculate Conception, Saint Patrick |
| Priests: | 60 |
| Footnotes: | [1] [2] |
| Border: | catholic |
| Headquarters: | Saint John, New Brunswick |
The Roman Catholic Diocese of Saint John, New Brunswick (la|Dioecesis Sancti Ioannis Canadensis) (erected 30 September 1842, as the Diocese of Saint John in America) is a suffragan of the Archdiocese of Moncton. It was renamed on 15 November 1924.
| Year | Along with | To form | |
|---|---|---|---|
| 1860 | Diocese of Chatham | ||
| 1936 | Diocese of Chatham | Archdiocese of Moncton |