Stalag 17 is a 1953 American war film that recounts the story of a group of American airmen confined in a German prisoner-of-war camp. The film focuses on one particular barracks, where the men come to suspect that one of their number is an informant.

The film was directed and produced by Billy Wilder, who with Edwin Blum adapted the screenplay from the Broadway play of the same name. The play was written by Donald Bevan and Edmund Trzcinski on the basis of their experiences as prisoners in Stalag 17B in Austria.

The film stars William Holden in an Oscar-winning performance, along with Don Taylor, Robert Strauss, Harvey Lembeck, Peter Graves, Neville Brand, Richard Erdman, Sig Ruman, and Otto Preminger. Strauss and Lembeck appeared in the original Broadway production.

Stalag 17 is a German prisoner-of-war camp "somewhere on the Danube" during World War II. One of its compounds holds 630 American airmen (all of whom are sergeants) and is overseen by camp warden Oberst von Scherbach. In December 1944, the men of Barracks 4 — led by appointed barracks chief "Hoffy" Hoffman and security officer Frank Price — arrange for the escape of fellow airmen Manfredi and Johnson. The pair are shot dead in the attempt, and the men believe they were betrayed by an informant. Suspicion falls on J. J. Sefton (Holden), an enterprising cynic who barters openly with the German guards for various luxuries. He also creates profitable ventures that distract from the mundanity of camp life: from organizing rat races for gambling, to an improvised distillery for brewing alcohol, to a makeshift telescope to spy on the Russian women from a neighboring compound. Clarence "Cookie" Cook, who narrates the story, serves as Sefton's naive and loyal aide.

The men of Barracks 4 do their best to manage the stress and boredom of imprisonment. This includes enduring the antics of barracks clowns "Animal" Kuzawa and Harry Shapiro, and listening for war news on a smuggled radio. Although their guard, Feldwebel Schulz, is jovial, he secretly retrieves hidden messages from a hollow chessboard piece (the black queen), and he straightens the looped cord of a dangling light bulb as a signal between himself and the informant. Just before Christmas, a recently captured Lieutenant Dunbar is assigned to Barracks 4 until he can be sent to an officers camp. Sgt. Bagradian, who accompanies Dunbar, reveals that Dunbar rigged a time bomb in transit and blew up a munitions train. Sefton recognizes Dunbar from officer's school. He believes Dunbar only passed because of his wealthy family, and this creates tension between them.

Schulz announces that an inspector from the Geneva Convention will arrive. Sefton bribes the guards to let him spend the day with the Russian women. The radio is later confiscated by Schulz. Concluding that Sefton was rewarded for revealing the radio, the men confront him when he returns, but Sefton denies he was responsible. Von Scherbach interrupts to arrest Dunbar as a saboteur; the men blame Sefton again, and they brutally beat him.

The next day, the inspector from Geneva arrives with Red Cross parcels—including 2,000 ping-pong balls, which the prisoners use to create smoke bombs. The inspector is told about Dunbar's removal. He warns von Scherbach that Dunbar cannot be convicted without proof lest there be war crime trials. Von Scherbach hands Schulz a black queen to be delivered to the informant. During the Christmas Eve celebrations, Price stealthily switches out the black queen, reads the hidden message, and resets the signal. Sefton, recovering from his beating, notices the signal afterwards and becomes suspicious. Price gets Bagradian to reveal the recipe of Dunbar's time bomb: a lit cigarette tucked into a matchbook. That night, an air raid siren forces the men to evacuate. Sefton hides and witnesses Price speaking German to Schulz, and demonstrating the time bomb as evidence against Dunbar.

On Christmas Day, the SS arrive to transport Dunbar to Berlin. While Hoffy has Price guard Sefton (who is still believed to be the informant), he gathers the men to rescue Dunbar. A riot and an ignited smoke bomb distract the guards, and Dunbar is taken to hide in a latrine's water tower until nightfall. After von Scherbach threatens to raze the camp, the men of Barracks 4 decide that one of them must help Dunbar escape. Price volunteers, and Sefton finally accuses him of being a German spy. Sefton interrogates Price and reveals the messaging system he used. The men are convinced. Price tries to flee, but he is quickly restrained and gagged.