Brain Donors is a 1992 American slapstick comedy film directed by Dennis Dugan and released by Paramount Pictures, loosely based on the Marx Brothers comedies A Night at the Opera and A Day at the Races (the first two films the Marx Brothers made for Metro-Goldwyn-Mayer after leaving Paramount). The film co-stars John Turturro, Mel Smith, and Bob Nelson in the approximations of the Groucho, Chico, and Harpo roles, with Nancy Marchand in the Margaret Dumont dowager role. It was executive produced by David and Jerry Zucker, through their Zucker Brothers Productions.

After the death of tycoon and philanthropist Oscar Winterhaven Oglethorpe, a ballet company is founded in his name by his widow, Lillian. Ambulance-chasing attorney Roland T. Flakfizer competes against Oglethorpe's former attorney, Edmund Lazlo, to be director of the company. Lazlo is chosen for the position after signing the greatest ballet dancer in the world, Roberto "The Great” Volare. Flakfizer — with assistance from his two associates Rocco and Jacques — earns a spot as co-director by wooing the wealthy widow and by signing the company's leading ballerina and her dancer boyfriend Alan Grant. The ensuing struggle between Flakfizer and Lazlo leads to comic hijinks, including a badger game involving a chorus girl and an opening-night performance ludicrously sabotaged by Flakfizer and his cohorts.

Minor roles include Eddie Griffin as a messenger, Franklin Cover as a doctor, Thomas Mikal Ford and Matthew Sussman as cops, Katherine LaNasa as a dancer, Billy Beck as a janitor, Sam Krachmalnick as a conductor, and Max Alexander as a stage manager.

Dennis Dugan began work on the film shortly after screening a rough cut of his film Problem Child for David Zucker. Soon after meeting to compare notes, Zucker sent Dugan a script by Pat Proft, and work began on the project in earnest. Initially, Proft was to be a co-producer and frequent Zucker brothers collaborator Jim Abrahams was to be a co-writer, but Abrahams was ultimately not credited as a screenwriter.

Dugan originally sought to cast Adam Sandler in the film, but the studio did not agree to it; however, this established a rapport with Sandler that led to Dugan directing several films with him. Dugan also stated that he unsuccessfully pursued Chris Farley and Jim Carrey for the lead role of Roland T. Flakfizer.

Principal photography began on December 10, 1990, and the film was largely shot in and around Los Angeles: Greystone Mansion (interiors); Los Angeles Herald-Examiner building, Echo Park Lake (exteriors), and the Warner Grand Theatre. Portions of the film were shot in Pasadena, California, at the Arden Villa (also called the Morton Estate) (exteriors), which was also a location where the Marx Brothers' Duck Soup was shot.

The project was filmed under the title Lame Ducks, but Paramount later changed the title to Brain Donors because it was "catchier", according to sources consulted by the Los Angeles Times.

The film's extended closing setpiece is a pastiche of Tchaikovsky ballet pieces, most notably Swan Lake (parodied in the film as Tears of the Swan). The choreographer for the film's dance scenes was John Carrafa. Costuming was handled by Robert Turturice. Mickey Gilbert was the stunt coordinator; Max Balchowsky and Ric Roman Waugh (credited as Rick Waugh) were among the stuntmen involved in production. The opening credits and closing scene of the film are claymation sequences designed by Will Vinton. The film is scored by Ira Newborn; Mark Mothersbaugh contributed the main and end titles and additional music.