Teorema, known as Theorem in the United Kingdom, is a 1968 Italian surrealist[2] psychological drama film written and directed by Pier Paolo Pasolini and starring Silvana Mangano, Terence Stamp and Massimo Girotti, with Anne Wiazemsky, Laura Betti, Andrés José Cruz Soublette, Alfonso Gatto and Carlo De Mejo.

In this film, an upper-class Milanese family is introduced to, and then abandoned by, an otherworldly man with a mysterious divine force.

Teorema has been sometimes incorrectly cited as the source for the 1986 American comedy film Down and Out in Beverly Hills; though there are similar themes, the latter is inspired by a much older stage play from around 1932.

He stops the passionate maid from committing suicide with a gas hose and tenderly consoles her; he befriends and sleeps with the frightened son, soothing his doubts and anxiety and endowing him with confidence; he seduces the bored and dissatisfied mother, giving her sexual joy and fulfillment; he cares for and comforts the despondent and ailing father; and he becomes emotionally intimate with the overprotected daughter, removing her childish innocence about men.

In the subsequent void of the stranger's absence, each family member is forced to confront what was previously concealed by the trappings of bourgeois life.

The maid returns to the rural village where she was born and is seen to perform miracles; ultimately, she immolates herself by having her body buried in dirt while shedding ecstatic tears of regeneration.

The daughter sinks into a catatonic state and is institutionalized; the son leaves the family home to become an artist, obsessively drawing the stranger's face; the mother seeks sexual encounters with young men; and the father strips himself of all material effects, handing his factory over to its workers, removing his clothes at a railway station and wandering naked across the slopes of Mount Etna, where he ultimately screams in primal rage and despair.

It begins with documentary-like images and then moves on to the opening credit with a dark volcanic desert, a home party scene, cuts of the factory in sepia tone, introduction of each family member in silence and sepia tone, and, then, the guest sitting in the back yard in colour.

In The Cinema of Economic Miracles: Visuality and Modernization in the Italian Art Film, Angelo Restivo assumes that Pasolini suggests that even documentary images, which depict facts, fail to show the truth.

[10][page needed] On the other hand, Viano believes that Pasolini's emphasis is not on homosexuality but rather on sexuality in general, because the guest has sex with each member of the household.

[7][page needed] Italian critic Morandini, author of a dictionary of cinema, claimed that "the theorem is demonstrated: the incapacity of modern—bourgeois—man to perceive, listen to, absorb and live the sacred.

The sketch comedy program Mr. Show aired a segment (series three, episode six) in which a suburban family is slowly revealed, over time, to have all individually had sexual affairs with David Cross, possibly in reference to the film.