The Cathedral of Saint Peter of Beauvais (Cathédrale Saint-Pierre de Beauvais) is an incomplete Roman Catholic cathedral located in Beauvais, in northern France. It is the seat of the Bishop of Beauvais, Noyon and Senlis. It is, in some respects, the most daring achievement of Gothic architecture, and consists only of a transept (sixteenth-century) and choir, with apse and seven polygonal apsidal chapels (thirteenth century), which are reached by an ambulatory.
The small Romanesque church of the tenth century, known as the Basse Œuvre, much restored, still occupies the site destined for the nave. The work was interrupted in 1284 by the collapse of some of the vaulting of the recently completed choir. This collapse is often seen as a disaster that produced a failure of nerve among the French masons working in Gothic style; modern historians have reservations about this deterministic view.