The Fin-de-Siècle Museum (Musée Fin-de-Siècle, Fin-de-Siècle Museum; "Museum of the Turn of the Century") is a museum in central Brussels, Belgium. It is dedicated to the full spectrum of the arts of the period between 1884, when the Société Libre des Beaux-Arts ("Free Society of Fine Arts") was founded Brussels, and 1914, the year of the outbreak of World War I. It is one of the constituent museums of the Royal Museums of Fine Arts of Belgium. The museum opened on 6 December 2013.
Artists represented in the museum's collection include Constantin Meunier, James Ensor, Henri Evenepoel, Fernand Khnopff, and Léon Spilliaert. The museum also celebrates the richness of the period in literature, architecture, photography, opera, music, and poetry, featuring works by Maurice Maeterlinck, Emile Verhaeren, Octave Maus, Victor Horta, Henry Van de Velde, Maurice Kufferath, and Guillaume Lekeu.
Important international artists of the period in the collection include Vincent van Gogh, Auguste Rodin, Georges Seurat, Paul Gauguin, and Edward Burne-Jones. The Gillon-Crowet gallery houses a collection of Art Nouveau furniture and decorative arts.
Constantin Meunier - Painted self-portrait.jpeg|''Self-portrait'', [[Constantin Meunier]], 1885
File:Fernand Khnopff - Portret van Marguerite - Portrait de Marguerite - Erfgoedfonds Koning Boudewijnstichting - Fonds du Patrimoine Fondation Roi Baudouin.jpg|''Portrait de Marguerite Khnopff'', [[Fernand Khnopff]], 1887
File:James Ensor, Les masques singuliers, 1892.jpg|''Les masques singuliers'', [[James Ensor]], 1892
File:Toulouse-Lautrec - Le Divan japonais, INHA.jpg|''Divan Japonais'', [[Henri de Toulouse-Lautrec]], 1893
File:La natura - Alfons Mucha.jpg|''La Nature'', [[Alphonse Mucha]], 1899–1900
File:Antonin daum e louis majorelle, lampade a tre braccia dente di leone, 1902.