One Flew Over the Cuckoo's Nest is a 1975 American psychological comedy-drama film[4] directed by Miloš Forman, based on the novel by Ken Kesey.

The film stars Jack Nicholson as a new patient at a mental institution and Louise Fletcher as the domineering head nurse.

Will Sampson, Danny DeVito, Sydney Lassick, William Redfield, Christopher Lloyd and Brad Dourif play supporting roles, with the latter two making their feature film debuts.

It is the second of three films to win all five major Academy Awards (Best Picture, Best Actor, Best Actress, Director, and Screenplay) following It Happened One Night (1934), and preceding 1991's The Silence of the Lambs.

In 1963 Oregon, Randle McMurphy is incarcerated for the statutory rape of a 15-year-old girl, (which he claims he committed under the assumption that she was an 18-year-old) with five previous arrests for assault.

The other patients include young, anxious, stuttering Billy Bibbit; Charlie Cheswick, who is prone to temper tantrums; delusional, child-like Martini; the articulate and repressed Dale Harding; belligerent and profane Max Taber; epileptics Jim Sefelt and Bruce Fredrickson; quiet but violent-minded Scanlon; tall, deaf-mute Native American Chief Bromden; and several others with chronic conditions.

Ratched sees McMurphy's lively, rebellious presence as a threat to her authority, to which she responds by confiscating and rationing the patients' cigarettes and suspending their card-playing privileges.

One night, he makes a bet with the other inmates that he can escape by tearing a hydrotherapy fountain off its hinges and throwing it out the window, but is unable to lift it.

Shortly after, he steals a charter bus, picks up his girlfriend Candy, and escapes with several patients to go fishing, exposing them to the outside world and encouraging them to discover their abilities and find self-confidence.

McMurphy is subjected to electroconvulsive therapy, and returns to the ward pretending to be brain-damaged before revealing that the treatment has made him even more determined to defeat Ratched.

McMurphy and Chief plan to throw a secret Christmas party for their friends after Ratched and the orderlies leave for the night before making their escape.

When she threatens to tell his mother, Billy cracks under the pressure and reverts to stuttering, before Ratched orders he be locked in a separate room as punishment.

Ratched tries to control the situation by calling for the day's routine to continue as usual, but her nonchalant reaction enrages McMurphy, who begins strangling her.

[2] Kesey participated in the early stages of script development, but withdrew after creative differences with the producers over casting and narrative point of view; ultimately he filed suit against the production and won a settlement.

Although Douglas and Zaentz were unaware that he had been his father's first choice to direct, they began considering him after Hauben showed them Forman's 1967 Czechoslovak film The Firemen's Ball.

"[2] Although Forman was suffering from a mental health crisis and refused to leave his Hotel Chelsea room in New York City for months, Douglas and Zaentz sent him a copy of the novel.

Ashby wanted 37-year-old Jack Nicholson to play McMurphy, but Douglas was unsure if he was right for the role and Forman's first choice was Reynolds.

Lambert's father often sold cars to Native American customers and six months later called Douglas to say: "the biggest sonofabitch Indian came in the other day!

"[2] Jeanne Moreau, Angela Lansbury, Colleen Dewhurst, Geraldine Page, Ellen Burstyn, Anne Bancroft, and Jane Fonda all were considered to portray Nurse Ratched before Lily Tomlin was ultimately cast in the role.

[20] Forman also considered Shelley Duvall for the role of Candy; coincidentally, she, Nicholson, and Scatman Crothers (who portrays Turkle) all later appeared as part of the main cast of The Shining.

[2] As Forman did not allow the actors to see the day's filming, this led to the cast losing confidence in him, while Nicholson also began to wonder about his performance.

[26] The production went over the initial budget of $2 million and over-schedule, but Zaentz, who was personally financing the movie, was able to come up with the difference by borrowing against his company, Fantasy Records.

Roger Ebert said: Miloš Forman's One Flew Over the Cuckoo's Nest is a film so good in so many of its parts that there's a temptation to forgive it when it goes wrong.

But it does go wrong, insisting on making larger points than its story really should carry, so that at the end, the human qualities of the characters get lost in the significance of it all.

[30] A.D. Murphy of Variety wrote a mixed review as well,[31] as did Vincent Canby in The New York Times: A comedy that can't quite support its tragic conclusion, which is too schematic to be honestly moving, but it is acted with such a sense of life that one responds to its demonstration of humanity if not to its programmed metaphors.

[32] The film opens and closes with original music by composer Jack Nitzsche, featuring an eerie bowed saw (performed by Robert Armstrong) and wine glasses.

These include the Best Actor for Jack Nicholson, Best Actress for Louise Fletcher, Best Direction for Forman, Best Picture, and Best Adapted Screenplay for Lawrence Hauben and Bo Goldman.

The website's critics consensus reads: "Jack Nicholson and Louise Fletcher are worthy adversaries in One Flew Over the Cuckoo's Nest, with Miloš Forman's more grounded and morally ambiguous approach to Ken Kesey's surrealistic novel yielding a film of outsized power.

[39] The film has been referenced several times on The Simpsons, including an episode where Homer is committed to an insane asylum and meets a man who believes himself to be Michael Jackson.

In an episode from the fourth season of It's Always Sunny in Philadelphia, titled "Sweet Dee Has a Heart Attack," Danny DeVito's character Frank Reynolds is part of subplot that directly parodies the film.