The film takes place during the German occupation of Rome, specifically January-May 1944, judging by the reference to the battle of Monte Cassino. Giorgio Manfredi, an engineer in civilian life, is now part of an Italian resistance group. The Nazis know about him and are hunting Rome for him, so he escapes to the apartment of his friend Francesco, who is also part of the resistance. Francesco is about to marry Pina, who is carrying his child.
Giorgio was supposed to smuggle some money out to resistance fighters in the hills, but can't leave the city now that the Germans are looking for him. He approaches Don Pietro, a sympathetic priest, and asks him to do it. Don Pietro agrees...but the Germans are closing in Giorgio's little ring.
- As the Good Book Says...: Don Pietro says "It is finished." when Giorgio has been tortured to death by the Germans.
- Badass Preacher: Don Pietro Pellegrini is a Catholic priest who helps lead the anti-Nazi resistance in Rome.
- Book Safe: A variation on this trope. Don Pietro is asked to carry some money to Resistance fighters. He's confused when the man he contacts hands him some books instead. As the man demonstrates, the books aren't real books, but Italian banknotes bound together between covers.
- Chummy Commies: Giorgio is a communist and antifascist. The Nazis try to use his politics and atheism to get Don Pietro to betray him. It doesn't work.
- Cold-Blooded Torture: The cells of the SS prison ring with the screams of torture victims. Near the end Giorgio is tortured with a blowtorch.
- Comforting Comforter: Francesco is looking after Marcello after Pina is murdered. He tucks Marcello in.
- Crapsack World: Wartime Italy.
- Driven to Suicide: The Austrian defector chooses to hang himself instead of facing torture or telling the SS what he knows.
- Face Death with Dignity: Don Pietro tells the priest giving him last rites that it is easy to die well, but difficult to live well. He demonstrates this by remaining calm and collected even as he is tied to a chair while a firing squad lines up behind him, especially when the altar boys from his parish show up at the fence to whistle a resistance signal in a demonstration of solidarity.
- Frying Pan of Doom: Don Pietro and Marcello get into the latter's building under the pretext of needing to pray for a bedridden old man (they are actually hiding evidence of resistance activities). Unfortunately, the man starts ranting about how he's not sick enough to need a priest, and as for the Germans and Fascists, they can go to Hell for all he cares. Don Pietro asks Marcello to hand him something, and a later scene reveals that he bashed the old man over the head with a frying pan.
- Good Shepherd: Don Pietro, who is working with the resistance.
- Hand Gagging: Don Pietro has to Hand Gag an old man to get him to shut up as the Germans ransack the building.
- In the Back:
- In the film's most iconic scene, Pina runs after the truck onto which Francesco and the other prisoners have been loaded; the Germans promptly shoot her in the back, leaving Don Pietro and Marcello respectively praying and crying over her dead body.
- For Don Pietro's execution, he is tied to a chair and shot from behind rather than in front.
- La Résistance: Giorgio is enmeshed with the Italian resistance—the "National Liberation Committee"—struggling to liberate their country after the Nazis occupied it in August 1943. All of his friends are working with the resistance as well. Even little Marcello, who is about ten, is leading his buddies in anti-German activities. They plant a bomb which blows up a fuel tank.
- Mercy Kill: The firing squad at Don Pietro's execution deliberately aim badly, since they cannot bring themselves to kill a priest. However, this leaves him mortally wounded, so Captain Hartmann steps forward and shoots him in the head to spare him the agony of a slow death.
- My God, What Have I Done?: Marina starts saying "what have I done?" pretty soon after the Germans arrest Giorgio on her tip.
- Not Afraid to Die: Both Giorgio and Don Pietro calmly show Major Bergmann that they will tell him nothing even in the face of torture. The Austrian who thinks that he cannot take the torture without staying silent picks the other way out.
- Off-into-the-Distance Ending: After Don Pietro is executed on the outskirts of Rome, Marcello and his buddies turn away and walk back towards the city, St. Peter's clearly visible in the distance.
- Pietà Plagiarism: Don Pietro cradles Pina after she is shot In the Back by the Germans.
- Reveal Shot: Don Pietro and Pina are walking away from the church altar. They look startled but keep walking. The camera pulls back as they walk, eventually revealing that a Nazi officer is waiting for them. (It turns out he's a deserter from Monte Cassino.)
- Ripped from the Headlines: Many of the scenes are reenactments of real events that had only occurred less than a year prior (filming started just two months after the Nazis left Rome), with the characters as thinly-veiled analogues for real people.
- Roof Hopping: Opens with Giorgio hurriedly ascending a flight of stairs to the roof of his apartment building, then clambering over a narrow gap to the next building. The Gestapo has come looking for him.
- Shell-Shocked Veteran: Captain Hartmann, a World War 1 veteran who drowns himself in alcohol every night to forget the bad things he had done.
- Shot at Dawn: Bergmann sends Don Pietro to the firing squad after knowing that he will get nothing from him. In a twist, the Italian soldiers refuse to have blood of a priest on their hands and deliberately miss their shots, only for Captain Hartmann to finish the job himself.
- Trust Password: Giorgio tells Don Pietro that when he takes the money to the men in the mountains, the man he's to give it to will be whistling popular tune "Morning in Florence".