Maguelone Cathedral (Cathédrale Saint-Pierre de Maguelone or Cathédrale Saint-Pierre-et-Saint-Paul de Maguelone) was the cathedral of the former Bishop of Maguelone until 1563, when the see was transferred to the newly created Bishopric of Montpellier. Now a totally isolated structure, it is situated on the once easily defensible peninsula that was the site of the original city of Maguelone, opposite the present Villeneuve-lès-Maguelone, Hérault, France.
The cathedral, constructed when the see was returned here in the 11th century from Substantion by Bishop Arnaud (1030-1060), is a Romanesque fortified building. Although parts, such as the towers, have been demolished, the main body of the building remains functional and is a registered national monument. It is run by a dedicated preservation society and is used for both religious and secular purposes.