The Key is an Italian erotic film directed by Tinto Brass. Set in Venice under the fascist regime in the early months of 1940, it recounts a tale of a voluptuous woman in her forties who is unable to respond to her husband but undergoes a belated sexual awakening with her daughter's fiancé, which enables her to please her husband at last. The film caused scandal in some quarters because it contains several explicit shots of nudity and sex scenes involving the well-known actress Stefania Sandrelli. However, the film ultimately obtained a decent level of commercial success.

Giovanni "Tinto" Brass is an Italian film director and screenwriter. In the 1960s and 1970s, he directed many critically acclaimed avant-garde films of various genres. Today, he is mainly known for his later work in the erotic genre, with films such as Caligula, Così fan tutte, Paprika, Monella and Trasgredire.