Leon Benois (Russian: Леонтий Николаевич Бенуа) (1856 in Peterhof – 1928 in Leningrad) was a Russian architect from the Benois family. He was the son of architect Nicholas Benois, the brother of artists Alexandre Benois and Albert Benois . He built the Roman Catholic cathedral of Notre-Dame in St Petersburg, the mausoleum of the Grand Dukes of Russia in the Peter and Paul Fortress, the Russian Chapel in Darmstadt, and the Alexander Nevsky Cathedral, Warsaw, among many other works. Benois served as Dean of the Imperial Academy of Arts (1903–06, 1911–17) and edited the architecture magazine "Zodchiy". He gave his name to Leonardo da Vinci's painting Madonna Benois which he inherited from his father-in-law and presented to the Hermitage Museum. Painter Nadia Benois was his daughter, and Sir Peter Ustinov was his grandson.