Diane is a 1956 American historical drama film about the life of Diane de Poitiers, produced by Metro-Goldwyn-Mayer, directed by David Miller, and produced by Edwin H. Knopf from a screenplay by Christopher Isherwood based on a story by John Erskine. The music score was composed by Miklós Rózsa, and Robert H. Planck was the cinematographer, who filmed in CinemaScope and Eastmancolor. The exceptionally lavish costumes were designed by Walter Plunkett.

The film stars Lana Turner, Pedro Armendáriz, Roger Moore, and Marisa Pavan, and features Sir Cedric Hardwicke, Torin Thatcher, Taina Elg, John Lupton, Henry Daniell, Melville Cooper and an early film appearance by Stuart Whitman. It was Turner's last film under her longtime MGM contract and thus marked another stage in the decline of the studio star system.