The diocese of Hải Phòng (Latin: Dioecesis Haiphongensis) is a Roman Catholic diocese in northern Vietnam. The bishop is Vincent Nguyên Văn Ban, since 2022.

The creation of the diocese in its present form was declared 24 November 1960. The earliest forms of Roman Catholic institutions appeared in that territory since 1655, with French and Spanish missionaries until the middle of the 20th century.

The diocese covers an area of 10,000 km², and is a suffragan diocese of the Archdiocese of Hanoi.

By 2004, the diocese of Hai Phòng had about 113,092 believers (2.4% of the population), 29 priests and 62 parishes.

Queen of the Rosary Cathedral in Hai Phong has been assigned as the Cathedral of the diocese.

Many migrant workers from other regions of Vietnam, who work in that busy port city, attend masses in Hai Phong.

In 2008, the Bishop of Hai Phong Diocese Joseph Vu Van Thien took part in World Youth Day 2008 in Sydney, Australia, where he presented a speech at the Homily at the Opening Mass for Vietnamese Youth.

Vicar apostolic		Period in office	Status	Reference
1	Bishop François Deydier, M.E.P.	November 25, 1678 – July 01, 1693	Died in office
2	Bishop Raimondo Lezzoli, O.P.	October 20, 1696 – January 18, 1706
3	Bishop Juan de Santa Cruz, O.P.	April 03, 1716 – August 14, 1721
4	Bishop Tommaso Sextri, O.P.	August 14, 1721 – August 08, 1737
5	Bishop Hilario di Jesu Costa, O.A.D.	August 08, 1737 – March 11, 1757
6	Bishop Santiago Hernández, O.P.	August 13, 1757 – February 06, 1777
7	Bishop Manuel Obellar, O.P.	January 29, 1778 – September 07, 1789
8	Bishop Feliciano Alonso, O.P.	October 01, 1790 – February 02, 1799
9	Bishop Ignacio Clemente Delgado Cebrián, O.P.	February 02, 1799 – July 12, 1838	Died in office, martyred.
10	Bishop Jerónimo Hermosilla Aransáez, O.P.	August 02, 1839 – November 01, 1861
11	Bishop Hilarión Alcáraz, O.P.	November 01, 1861 – 1868	Resigned
12	Bishop Antonio Colomer, O.P.	February 11, 1870 – June 01, 1883	Transferred to Northern Tonkin
13	Bishop José Terrés, O.P.	May 29, 1883 – April 02, 1906	Died in office
14	Bishop Nicasio Arellano, O.P.	April 11, 1906 – April 14, 1919	Resigned
15	Bishop Francisco Ruiz de Azúa Ortiz de Zárate, O.P.	April 14, 1919 – December 03, 1924	Remained as Vicar apostolic of Hai Phòng.

Vicar apostolic			Period in office	Status	Reference
15		Bishop Francisco Ruiz de Azúa Ortiz de Zárate, O.P.	December 03, 1924 – May 22, 1929	Died in office
16		Bishop Alejandro García Fontcuberta, O.P.	May 31, 1930 – February 14, 1933
17		Bishop Francisco Gómez de Santiago, O.P.	February 18, 1933 – 1952
18		Bishop Joseph Trương Cao Ðại	January 08, 1953 – 1960	Resigned
–		Bishop Joseph-Marie-Pierre Khuất Văn Tạo	May 07, 1955 – November 24, 1960	Apostolic Administrator

Bishop			Coat of arms	Period in office	Status	Reference
1		Bishop Joseph-Marie-Pierre Khuất Văn Tạo		November 24, 1960 – August 19, 1977	Died in Office
2		Bishop Joseph Marie Nguyễn Tùng Cương		January 10, 1979 – February 10, 1999
3		Bishop Joseph Vũ Văn Thiên		November 26, 2002 – November 17, 2018	Transferred to Hanoi
–		Archbishop Joseph Vũ Văn Thiên		November 17, 2018 – March 19, 2022	Apostolic Administrator
4		Bishop Vincent Nguyễn Văn Bản		March 19 2022–present	Current bishop

Coadjutor Vicar Apostolic of Eastern Tonking (1716-1919)

		Period in office	Reference
1	Bishop Tommaso Sextri, O.P.	March 18, 1716 – August 14, 1721
2	Bishop Hilario di Jesu Costa, O.A.D.	October 03, 1735 – April 08, 1737
3	Bishop Ignacio Clemente Delgado Cebrián, O.P.	February 11, 1794 – February 02, 1799
4	Bishop Domingo Henares de Zafra Cubero, O.P.	September 09, 1800 – June 25, 1838
5	Bishop Romualdo Jimeno Ballesteros, O.P.	August 02, 1839 – June 20, 1845
6	Bishop Hilarión Alcáraz, O.P.	September 05, 1848 – November 01, 1861
7	Bishop Gaspar Fernández, O.P.	March 27, 1863 – July 19, 1868
8	Bishop José Terrés, O.P.	February 06, 1875 – May 29, 1883
9	Bishop Francisco Ruiz de Azúa Ortiz de Zárate, O.P.	June 19, 1917 – April 14, 1919

Coadjutor Vicar Apostolic of Hai Phòng (1932-1933)

		Period in office	Reference
–	Bishop-elect Francisco Gomez de Santiago, O.P.	November 28, 1932 – February 18, 1933

20°51′40″N 106°40′51″E / 20.8610°N 106.6807°E / 20.8610; 106.6807