- Backed by the Pentagon: The T-34 tanks seen in the film were supplied by them. All the Russian extras are also obviously played by members of the Yugoslav People's Army (they speak Serbo-Croatian).
- Based on a True Story: Not well known, but the author of the novel (Willi Heinrich) served as an officer in the 101st Light Infantry Division. He served there with Feldwebel Johann Schwerdfeger who was decorated with the Iron Cross 2nd Class, 1st Class, Knight's Cross, and Oakleaves to the Knight's Cross. A review of the unit history of the division reveals major similarities between Schwerdfeger and Steiner, including serving at Izyum and fighting at Hill 121.4, a real life location near Krymskaya.
- California Doubling: The film was largely shot in Yugoslavia.
- Casting Gag: James Mason played a senior German officer who is faced with the scandal of an officer taking credit for the heroic deeds of a dead man. He faced the same scenario in The Blue Max.
- Dawson Casting: At 48, James Coburn was widely felt to be too old to play Corporal Steiner. The man his character was based on, Johann Schwerdfeger, was only 28 in the summer of 1943.
- Duelling Movies: With A Bridge Too Far, another British-made auteur film chronicling famous military defeats in World War II. Maximilian Schell was in both movies.
- Fake Nationality: Steiner (played by American James Coburn) and Brandt and Kiesel (played by British actors James Mason and David Warner) as German soldiers. Native German actors make up a decent size of the cast though, notably Maximilian Schell, who plays Stransky.
- International Coproduction: This was a joint Anglo-German production between EMI Films and ITC Entertainment of London and Rapid Films GmbH from Munich.
- Throw It In!: Maximilian Schell's stumbling by the railway track in the final scene was actually an on set accident during filming and not scripted (Sam Peckinpah simply hadn't enough film left to retake the sequence).
- Writing by the Seat of Your Pants: The film's ending is not the one in the script. The production had ran out of money, so Sam Peckinpah got James Coburn to improvise.
Trivia / Cross of Iron