The French architect Pierre de Montreuil (active ca. 1231-1266/1267) was a great exponent of the Rayonnant Gothic style of architecture.

The exact relationship of Pierre de Montreuil, or Montereau, with Eudes de Montreuil, Gerbert de Montreuil, and other notable figures of the 13th century bearing the name of Montreuil is not certain, especially as references to Pierre de Montereau seem to apply to this same architect. He was a pupil of Jean de Chelles, a leading Parisian master of Rayonnant Gothic architecture.

Montreuil and his nephew, Raoul de Montreuil, probably attracted the attention of King Louis IX through their rebuilding of the upper choir (1231-1239), the transept, and the nave (completed in 1281 after Montreuil's death) of the Basilica at Saint-Denis near Paris. The King must then have commissioned Montreuil to build his private and splendid Cistercian abbey at Royaumont (Oise), founded in 1228 and consecrated in 1238. Here Louis, inclined...