Un Chien Andalou (French pronunciation: [œ̃ ʃjɛ̃ ɑ̃dalu], An Andalusian Dog) is a 1929 silent surrealist short film by the Spanish director Luis Buñuel and artist Salvador Dalí. It was Buñuel's first film and was initially released in 1929 to a limited showing in Paris, but became popular and ran for eight months.

The film has no plot in the conventional sense of the word. The chronology of the film is disjointed, jumping from the initial "once upon a time" to "eight years later" without the events or characters changing very much. It uses dream logic in narrative flow that can be described in terms of then-popular Freudian free association, presenting a series of tenuously related scenes.

The film opens with a title card reading "Once upon a time". A middle-aged man (Luis Buñuel) sharpens his razor at his balcony door and tests the razor on his thumb. He then opens the door, and idly fingers the razor while gazing at the moon, about to be engulfed by a thin cloud, from his balcony. There is a cut to a close-up of a young woman (Simone Mareuil) being held by the man as she calmly stares straight ahead. Another cut occurs to the moon being overcome by the cloud as the man slits the woman's eye with the razor, and the vitreous humour spills out from it.