Murder on the Orient Express is a 1974 British mystery film directed by Sidney Lumet, produced by John Brabourne and Richard Goodwin, and based on the 1934 novel of the same name by Agatha Christie.

The film features the Belgian detective Hercule Poirot (Albert Finney), who is asked to investigate the murder of an American business tycoon aboard the Orient Express train.

The suspects are portrayed by an all-star cast, including Lauren Bacall, Martin Balsam, Ingrid Bergman, Sean Connery, John Gielgud, Jean-Pierre Cassel, Vanessa Redgrave, Michael York, Rachel Roberts, Jacqueline Bisset, Anthony Perkins, Richard Widmark and Wendy Hiller.

His old friend, Signor Bianchi, a director of the company that owns the rail line, arranges Poirot's accommodation after all the first-class compartments are uncharacteristically sold out during the off-season.

Other passengers include American socialite Harriet Belinda Hubbard; English governess Mary Debenham; Swedish missionary Greta Ohlsson; American businessman Samuel Ratchett, with his secretary/translator Hector McQueen and English valet Edward Beddoes; Italian-American car salesman Antonio Foscarelli; elderly Russian Princess Natalia Dragomiroff and her German maid Hildegarde Schmidt; Hungarian Count Rudolf Andrenyi and his wife Elena; British Army Colonel John Arbuthnott; and American theatrical agent Cyrus B. Hardman.

When the train stops in Belgrade, Bianchi gives Poirot his compartment and shares a coach with Greek physician Stavros Constantine.

Poirot finds a charred letter fragment revealing Ratchett's true identity: American gangster Lanfranco Cassetti who, with an accomplice, had carried out Daisy's kidnapping and murder.

Interviewing the passengers individually, Poirot learns McQueen is the son of the District Attorney from the kidnapping case and knew Mrs. Armstrong; Beddoes was a British Army batman; Greta Ohlsson has been to America; Countess Andrenyi's maiden name is Grünwald (German for "Greenwood", Mrs. Armstrong's maiden name); Conductor Pierre's daughter died five years earlier of scarlet fever; Colonel Arbuthnott and Miss Debenham will marry once he has divorced his philandering wife; and Princess Dragomiroff was Sonia's godmother.

Hubbard is revealed to be Linda Arden, mother of Sonia Armstrong and Helena Andrenyi, and the organizer of this "extraordinary revenge".

In the end, according to Christie's husband, Sir Max Mallowan, "Agatha herself has always been allergic to the adaptation of her books by the cinema, but was persuaded to give a rather grudging appreciation to this one."

According to one report, Christie gave approval because she liked the previous films of the producers, Romeo and Juliet and Tales of Beatrix Potter.

[9] Richard Rodney Bennett's Orient Express theme has been reworked into an orchestral suite and performed and recorded several times.

It was performed on the original soundtrack album by the Orchestra of the Royal Opera House, Covent Garden under Marcus Dods.

Nat Cohen claimed it was the first film completely financed by a British company to make the top of the weekly US box office charts in Variety.

[15] Roger Ebert gave the film three stars out of four, writing that it "provides a good time, high style, a loving salute to an earlier period of filmmaking".

[16] The New York Times's chief critic of the era, Vincent Canby, wrote [...] had Dame Agatha Christie's Murder on the Orient Express been made into a movie 40 years ago (when it was published here as Murder on the Calais Coach), it would have been photographed in black-and-white on a back lot in Burbank or Culver City, with one or two stars and a dozen character actors and studio contract players.

An earlier adaptation could have interfered with plans to produce this terrifically entertaining super-valentine to a kind of whodunit that may well be one of the last fixed points in our inflationary universe.