Under Capricorn is a 1949 British historical thriller film directed by Alfred Hitchcock about a man who is in love with a woman who turns out to be an alcoholic. The film was based on the novel Under Capricorn (1937) by Helen Simpson, with a screenplay by James Bridie. It was adapted to the screen by Hume Cronyn. This was Hitchcock's second film in Technicolor, and like the preceding color film Rope (1948), it also featured 10-minute takes.
The film is set in colonial Sydney, New South Wales, Australia during the early 19th century. Under Capricorn is one of several Hitchcock films that are not typical thrillers; instead it is a mystery involving a love triangle. Hitchcock considered it to be one of his worst films and a disaster. Although the film is not exactly a murder mystery, it does feature a previous killing, a "wrong man" scenario, a sinister housekeeper, class conflict, and very high levels of emotional tension, both on the surface and underneath.
The title "Under Capricorn" references the Tropic of Capricorn, which bisects Australia. Capricornus is a constellation; Capricorn is an astrological sign dominated by the goat, which is a symbol of sexual desire.