The Roman Catholic Diocese of Porto Novo (Latin: Dioecesis Portus Novi) is a diocese located in the city of Porto Novo in the ecclesiastical province of Cotonou in Benin.

• 5 April 1954: Established as Apostolic Vicariate of Porto Novo from Apostolic Vicariate of Ouidah
• 14 September 1955: Promoted as Diocese of Porto Novo

The Cathedral of the diocese is Cathédrale Notre Dame de l’Immaculée Conception in Porto Novo.

• Bishops of Porto Novo (Roman rite), in reverse chronological order
  • Bishop Aristide Gonsallo: 24 October 2015 – Present
  • Bishop René-Marie Ehuzu, C.I.M.: 3 January 2007 – 17 October 2012
  • Bishop Marcel Honorat Léon Agboton: 29 January 2000 – 5 March 2005, appointed Archbishop of Cotonou
  • Bishop Vincent Mensah: 21 September 1970 – 29 January 2000
  • Bishop Noël Boucheix, S.M.A.: 6 July 1958 – 1 January 1969

• Roman Catholicism in Benin

• GCatholic.org

6°28′19″N 2°37′09″E / 6.47194°N 2.61917°E / 6.47194; 2.61917