The Section d'Or ("Golden Section"), also known as Groupe de Puteaux or Puteaux Group, was a collective of painters, sculptors, poets and critics associated with Cubism and Orphism. Based in the Parisian suburbs, the group held regular meetings at the home of the Duchamp brothers in Puteaux and at the studio of Albert Gleizes in Courbevoie. Active from 1911 to around 1914, members of the collective came to prominence in the wake of their controversial showing at the Salon des Indépendants in the spring of 1911. This showing by Albert Gleizes, Jean Metzinger, Robert Delaunay, Henri le Fauconnier, Fernand Léger and Marie Laurencin (at the request of Apollinaire), created a scandal that brought Cubism to the attention of the general public for the first time.

The Salon de la Section d'Or, held October 1912—the largest and most important public showing of Cubist works prior to World War I—exposed Cubism to a wider audience still. After the war, with support given by the dealer Léonce Rosenberg, Cubism returned to the front line of Parisian artistic activity. Various elements of the Groupe de Puteaux would mount two more large-scale Section d'Or exhibitions, in 1920 and in 1925, with the goal of revealing the complete process of transformation and renewal that had transpired since the onset of Cubism.

The group seems to have adopted the name "Section d'Or" as both an homage to the mathematical harmony associated with Georges Seurat, and to distinguish themselves from the narrower style of Cubism developed in parallel by Pablo Picasso and Georges Braque in the Montmartre quarter of Paris. In addition, the name was to highlight that Cubism, rather than being an isolated art-form, represented the continuation of a grand tradition; indeed, the golden ratio, or golden section (French: Section d'Or), had fascinated Western intellectuals of diverse interests for at least 2,400 years.

The Puteaux Group (an offshoot of la Société Normande de Peinture Moderne) organized their first exhibition under the name Salon de la Section d'Or at the Galerie La Boétie in Paris, October 1912. Albert Gleizes and Jean Metzinger, in preparation for the Salon de la Section d'Or, published a major defense of Cubism, resulting in the first theoretical essay on the new movement, entitled Du "Cubisme" (published by Eugène Figuière in 1912, translated to English and Russian in 1913).

Following the 1911 Salon exhibitions, the group formed by Le Fauconnier, Metzinger, Gleizes, Léger and R. Delaunay expanded to include several other artists; Alexander Archipenko, Joseph Csaky, Roger de La Fresnaye, Juan Gris, and Jean Marchand, who were virtually unknown to the public before the Salon des Indépendants of 1911, began to frequent Puteaux and Courbevoie. František Kupka had lived in Puteaux for several years in the same complex as Jacques Villon. Francis Picabia was introduced to the circle, perhaps by Guillaume Apollinaire (usually accompanied by Marie Laurencin) with whom he had recently become friendly. Most importantly was the contact established with Metzinger and the Duchamp brothers, who exhibited under the names of Jacques Villon, Marcel Duchamp and Duchamp-Villon. The opening address was given by Apollinaire. The participation of many of these artists in the formation of Les Artistes de Passy in October 1912 was an attempt to transform the Passy district of Paris into yet another art-centre; a further sign of a growing emphasis on communal activity that would culminate in the Section d'Or exhibit.

The idea of the Section d'Or originated in the course of conversations between Gleizes, Metzinger and Jacques Villon. The group's title was suggested by Villon, after reading a 1910 translation of Leonardo da Vinci's A Treatise on Painting by Joséphin Péladan. Péladan attached great mystical significance to the golden section (French: nombre d'or), and other similar geometric configurations. For Villon, this symbolized his belief in order and the significance of mathematical proportions, because it reflected patterns and relationships occurring in nature. Jean Metzinger and the Duchamp brothers were passionately interested in mathematics. Jean Metzinger, Juan Gris and possibly Marcel Duchamp at this time were associates of Maurice Princet, an amateur mathematician credited for introducing profound and rational scientific arguments into Cubist discussions. The name 'Section d'Or' represented simultaneously a continuity with past traditions and current trends in related fields, while leaving open future developments in the arts.

Art historian Daniel Robbins argued that in addition to referencing the mathematical golden section, the term associated with the Salon Cubists also refers to the name of the earlier Bandeaux d'Or group, with which Albert Gleizes and other former members of the Abbaye de Créteil had been deeply involved.

The 1912 Salon de la Section d'Or was arguably the most important pre-World War I Cubist exhibition. In the previous year the Cubists and a large number of their associates had exhibited at the Galerie de l'Art Contemporain (rue Tronchet, Paris) under the auspices of the Société Normande de Peinture Moderne. This exhibition had received some attention in the press (l'Autorité and Paris Journal), though due to the diversity of the works presented it had been referred to as an exposition des fauves et cubistes. The Salon de la Section d'Or, however, was generally accepted as being entirely Cubist in nature. Over 200 works were displayed, and the fact that many of the artists showed artworks representative of their development from 1909 to 1912 gave the exhibition the allure of a Cubist retrospective.