Factual error: At the beginning of the movie, Patton is reviewing Morrocan troops during a formal parade. This includes a scene of camel mounted soldiers at attention lined up side by side. These soldiers are armed with the French MAT 49 submachine gun. This weapon was first manufactured in 1949, several years after World War Two had ended.
Factual error: In a scene set in 1944 France, shortly after D-Day, Patton is riding in a very distinctive type of Jeep that first went into production in 1953. Another Jeep in that same scene dates from 1950 onwards.
Factual error: Patton arrives at Bradley's mobile HQ just after D-Day. As his jeep pulls up you can see the truck that pulls the HQ trailer. It appears to be a Mack Model "B", which did not enter production until 1953.
Factual error: When Patton is given command of Third Army in France in 1944, he says that the assassination attempt on Hitler took place several days ago. Later on we see Field Marshal Rommel in a German command HQ looking quite healthy. Rommel was actually severely wounded three days prior to the attempt on Hitler and was in the hospital.
Continuity mistake: When the two Jeeps arrive at the Kasserine Pass to survey the results of the battle, the second Jeep comes to stop just short of running over a dead soldier. At the end of the scene, the same Jeep drives away, going forward as if to run over that body, but the body has vanished.
Factual error: During the early portions of the film, General Bradley's Jeep is a proper WWII Willys Jeep Model MB (wipers on top of windshield), but the second Jeep that follows Bradley's is a 1950-1952 Model M38 (wipers below windshield) which won't exist until five years after WWII ends.
Continuity mistake: When the three small boys run up and salute Patton, the middle boy stops with the other two slightly behind him to each side, and is the first to salute. When the camera angle changes to view them from in front, the middle boy is instantly behind the other two, and is the last to salute.
Factual error: In the scene of the high level meeting during the initial stages of the Battle of the Bulge, Bedell Smith is conducting the meeting in General Eisenhower's behalf. In fact, General Eisenhower was present at the meeting.
Factual error: In the washroom scene where Gen. Montogomery is speaking with Gen. Smith; Monty breathes on the mirror in order to make a drawing of Sicily. The condensed "breath" remains far too long, the same happens when Smith makes his drawing on the mirror.
Factual error: Before the Battle of El Gattar, Patton is shown reading a book on tank warfare purportedly written by Field Marshal Rommel, his German opponent. Rommel in fact wrote a book on infantry fighting and tactics based on his experiences in World War I. He never wrote a book on tank combat.
Other mistake: During the early part of the movie, when Patton is in Morocco, you can see two kids visibly mugging for the camera as they do cutaways on two distinct occasions.
Factual error: The drum major leading the British pipes and drums into Messina is a corporal wearing the usual two point-down chevrons on his upper arm. British Army drum majors, who all hold a minimum rank of sergeant, wear four point-up chevrons on their lower arm (on a leather strap if in shirt-sleeve order).
Factual error: Patton wears two overseas service bars (one awarded for every six months' service outside the USA from 7 December 1941) until he goes to Normandy to take over the Third Army. On the plane over he is suddenly wearing four bars. He would have received his third bar before he arrived in Normandy, and his fourth afterwards.
Character mistake: While General Patton is in Malta as a decoy for a fake Greek invasion, he gives some aides a tour of the fortifications there and tells them that they were "defended by 400 Knights of Malta and 800 mercenaries against a force of 40,000 Turks." He is referring to the Siege of Malta in 1565, but the date he gives is 1528.
Other mistake: In the scene showing Patton's arrival in London, stepping out of a Packard limousine in the night, the car shown is a postwar model year, e.g. 1948. Patton did favor Packard cars, but this one could not have existed at the time.