550 Madison Avenue is a postmodern skyscraper on Madison Avenue between 55th and 56th Streets in the Midtown Manhattan neighborhood of New York City. Designed by Philip Johnson and John Burgee with associate architect Simmons Architects, the building is a 647-foot-tall (197-meter), 37-story office tower with a facade made of pink granite. It was completed in 1984 as the headquarters of AT&T Corp. and later became the American headquarters of Sony. A four-story granite annex to the west was demolished and replaced with a shorter annex in the early 2020s.

Postmodern architecture is a style or movement which emerged in the late 1950s as a reaction against the austerity, formality, and lack of variety of modern architecture, particularly in the international style advocated by Philip Johnson and Henry-Russell Hitchcock. The movement was introduced by the architect and urban planner Denise Scott Brown and architectural theorist Robert Venturi in their 1972 book Learning from Las Vegas. The style flourished from the 1980s through the 1990s, particularly in the work of Scott Brown & Venturi, Philip Johnson, Charles Moore and Michael Graves. In the late 1990s, it divided into a multitude of new tendencies, including high-tech architecture, neo-futurism, new classical architecture, and deconstructivism. However, some buildings built after this period are still considered postmodern.