William Nelson Copley (American, January 24, 1919–May 7, 1996) was a painter and patron of the arts of some renown whose late Surrealist works have been seen as an early part of the American Pop Art movement of the 1950s and 1960s. Copley didn't enter the art world as a painter; instead, he became a patron to the arts in 1947. At this time, he opened an art gallery in Beverly Hills to display Surrealist Art, after discovering the Surrealist movement on a trip to Mexico. In his gallery, Copley displayed the works of artists including Rene Magritte (Belgian, 1898–1967), Max Ernst (German, 1891–1976), Yves Tanguy (French, 1900–1955), Roberto Matta (Chile 1911–2002), Joseph Cornell (1903–1972), and Man Ray (American 1890–1976). During the single year of the gallery's operation, Copley painted part-time, turning to full-time painting once the galley closed from lack of sales.

After the close of the gallery, the artist moved to Paris. During the 1950s and 1960s, while living and working in Paris, Copley painted a collection of Surrealist work featuring classic American images presented with humorous and ironic undertones. The first exhibition of his work was in 1951, in Los Angeles at Royer's Book Shop. This exhibition was followed by further showings in New York, Venice, Paris, and London. Copley’s paintings were a combination of the major influences on his art; he mixed Mexican and American Folk Art with the Modern Surrealist look to create the early Pop Art look for which he has become noted. In the 1970s, his work continued to evolve, featuring more erotic content. In 1974, Copley exhibited this new line of work, calling the exhibition CPLY X-Rated. Though his new work received little recognition in the United States, it encountered a wider appeal when exhibited in Europe.

Copley's paintings have been widely exhibited, appearing at the Museum of Modern Art in New York, the Tate Gallery in London, and the Art Institute of Chicago. As a patron of the arts, he began the William and Noma Copley Foundation in 1953. The foundation, which later changed its name to the Cassandra Foundation, provided small grants for artists. The foundation also gave the last work of foundation board member and painter Marcel Duchamp (French 1887–1968), the painting L'Etant Donnes, to the Philadelphia Museum of Art. Copley's paintings were primarily acrylics on linen and canvas, and his writings included the essay Portrait of the Artist as a Young Art Dealer as well as the news columns he wrote as a columnist for his father's newspapers. The artist died on May 7, 1996.