Section d’Or, Paris-based association of Cubist painters; the group was active from 1912 to about 1914.

The group’s name was suggested by the painter Jacques Villon, who had developed an interest in the significance of mathematical proportions such as the ancient concept of the golden section, the section d’or. The name thus reflects the Cubist artists’ concern with geometric forms, although Villon and Juan Gris were the only Cubists who directly applied such concepts to their work. The principal members of the group were Robert Delaunay, Marcel Duchamp, Raymond Duchamp-Villon, Albert Gleizes, Juan Gris, Roger de La Fresnaye, Fernand Léger, André Lhote, Louis Marcoussis, Jean Metzinger, Francis Picabia, and André Dunoyer de Segonzac.

In 1912 the group first exhibited together at the Galerie la Boétie in Paris, and it also published a short-lived magazine entitled Section d’Or. The start of World War I in 1914 ended the activities of the group, which had never been more than a loose association.