The story follows a San Francisco private detective and his dealings with three unscrupulous adventurers, all of whom are competing to obtain a jewel-encrusted falcon statuette.

The Maltese Falcon has been named as one of the greatest films of all time by Roger Ebert and Entertainment Weekly,  and was cited by Panorama du Film Noir Américain as the first major film noir.

The film premiered on October 3, 1941 in New York City, and was selected for inclusion in the Library of Congress' National Film Registry in 1989.

Plot
In 1941 San Francisco, private investigators Sam Spade (Humphrey Bogart) and Miles Archer (Jerome Cowan) meet prospective client Miss Ruth Wonderly (Mary Astor). She claims to be looking for her missing sister, who is involved with a man named Floyd Thursby. Wonderly is to meet Thursby. After receiving a substantial retainer, Archer volunteers to follow her that night and help get her sister back.

That night, Spade is informed that Archer has been killed. He meets his friend, Police Detective Tom Polhaus (Ward Bond), at the murder scene. He then calls Wonderly's hotel, but she has checked out. He is grilled by Polhaus and his supervisor, Lieutenant Dundy (Barton MacLane), who inform him that Thursby was also murdered that same evening. Dundy suggests that Spade had the opportunity and motive to kill Thursby, who likely killed Archer. Archer's widow (Gladys George), with whom Spade had had an affair, believes that Spade shot his partner so he could have her.
 
Later that morning, Spade meets Wonderly, now calling herself Brigid O'Shaughnessy. She explains that Thursby was her partner and probably killed Archer, but claims to have no idea who killed Thursby. Spade agrees to investigate the murders.

At his office, Spade meets Joel Cairo (Peter Lorre), who first offers him a $5,000 fee to find a "black figure of a bird," then pulls a gun on him in order to search for it. Spade manages to knock Cairo out and go through his belongings. When Cairo revives, he hires Spade. Later that evening, Spade tells O'Shaughnessy about Cairo. When Cairo shows up, it becomes clear that Spade's acquaintances know each other. Cairo becomes agitated when O'Shaughnessy reveals that the "Fat Man" is in San Francisco.

In the morning, Spade goes to Cairo's hotel, where he spots Wilmer (Elisha Cook, Jr.), a young man who had been following him earlier. He gives Wilmer a message for his boss, Kasper Gutman (Sydney Greenstreet), the "Fat Man". Spade meets Gutman. Gutman begins to talk about the Falcon, but becomes evasive, causing Spade to storm out. Later, Wilmer takes Spade at gunpoint to see Gutman. Spade overpowers Wilmer, but meets with Gutman anyway. Gutman relates the history of the Maltese Falcon. He offers Spade $25,000 for the bird and a quarter of the proceeds from its sale. Then Spade passes out; his drink was spiked. Wilmer, Gutman and Cairo (who had been in the other room) depart.

When Spade awakens, he searches the suite and finds a newspaper with the arrival time of the freighter La Paloma circled. He goes to the dock, only to find the ship on fire, so he returns to his office. A man (Walter Huston) clutching a bundle wrapped in newspaper bursts in and staggers toward Spade before dying. The contents of his wallet identify the dead man as Captain Jacobi of the La Paloma. The bundle contains the Maltese Falcon.

The phone rings. O'Shaughnessy gives an address and then screams before the line goes dead. Spade stashes the package in a bus terminal baggage room, then goes to the address. It turns out to be an empty lot. Spade returns home and finds O'Shaughnessy hiding in a doorway. He takes her inside, and finds Gutman, Cairo, and Wilmer waiting for him, guns drawn. Gutman gives Spade $10,000 for the Falcon, but Spade tells them that part of his price is someone he can turn over to the police for the murders of Archer, Thursby, and Captain Jacobi. Spade suggests Wilmer as the best choice, since he certainly killed Thursby and Jacobi. After some intense negotiation, Gutman and Cairo agree; Wilmer is knocked out in a scuffle. Spade gets the details of what happened and who killed whom, so that he can present a convincing story to the police along with Wilmer.

Just after dawn, Spade calls his secretary, Effie Perrine (Lee Patrick), to bring him the bundle. However, when Gutman inspects the black statuette, he discovers that it is a fake. He suggests that he and Cairo return to Istanbul to continue their quest. After they leave, Spade calls the police and tells them where to pick up the pair. Spade then angrily confronts O'Shaughnessy, telling her he knows she killed Archer to implicate Thursby, her unwanted accomplice. O'Shaughnessy cannot believe that Spade would turn her over to the police, but he does, despite his feelings for her.

Reception
Following a September 1941 preview, Variety called it "one of the best examples of actionful and suspenseful melodramatic story telling in cinematic form":

"Unfolding a most intriguing and entertaining murder mystery, picture displays outstanding excellence in writing, direction, acting and editing—combining in overall as a prize package of entertainment for widest audience appeal. Due for hefty grosses in all runs, it's textured with ingredients presaging numerous holdovers in the keys—and strong word-of-mouth will make the b.o. wickets spin."

Upon its release, Bosley Crowther called it "the best mystery thriller of the year", saying "young Mr. Huston gives promise of becoming one of the smartest directors in the field"; according to Crowther, "the trick which Mr. Huston has pulled is a combination of American ruggedness with the suavity of the English crime school—a blend of mind and muscle—plus a slight touch of pathos."

The film received three nominations at the 14th Academy Awards: Best Picture, Sydney Greenstreet for Best Supporting Actor, and John Huston for Best Adapted Screenplay.

As a result of the film's success, Warner Brothers immediately made plans to produce a sequel entitled The Further Adventures of the Maltese Falcon, which Huston was to direct in early 1942. However, due to Huston's high demand as a director and unavailability of the major cast members, the sequel was never made.

The film has been named as one of the greatest films of all time by Roger Ebert and Entertainment Weekly.

In 1989, The Maltese Falcon was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant", going in the first year of voting.