Deliberate mistake: When Wyatt comes out of the Orientalist and joins his brothers in the street to tell them he's acquired a quarter interest in a game, a herd of cattle is passing them in the street but there's no dust kicked up by the cattle, when in reality there would be a lot of dust on a dry desert street in Arizona.
Continuity mistake: When Curly Bill is shooting up the town while drunk, he fires about 10 more rounds than his six shooter can hold without reloading (so too many shots even if he had a second gun), and still has a round remaining when he shoots Marshal Fred White. In the 1880 court hearing held after Marshal White's death, Curly Bill still had 5 rounds remaining in his pistol.
Factual error: In the scene just before the fight at the O.K. Corral, Wyatt is talking to his brothers and Doc on the porch of the town marshal's office. There is an American flag flying behind him with 50 stars on it when in fact there were only 38 stars on the flag in 1881.
Factual error: During the gunfight in the lot behind the OK Corral, Tom McLaury is firing a six shooter at Doc just before Doc fires his shotgun in the air to scare Tom's horse away. The mistake is that Tom McLaury wasn't armed during the actual gunfight. He was shot by Doc while he was reaching for the rifle he had stored in his saddle. (01:14:58)
Revealing mistake: When Wyatt Earp and the actress, whom he marries later in the movie, meet on horseback, they go on a fast paced ride that concludes after going down a steep hill. If you look at the actress' feet, you will see she is riding side-saddle - a very difficult feat considering the riding they do. If you look closely you can see her real leg, safely on the other side of the horse. The side-saddle leg must be fake.
Factual error: Three of the Earp brothers arrived in Tombstone on December 1, 1879. They served as lawmen during 1880/81 and fought the Cowboys in the famous gunfight on October 26, 1881, They left the area in April 1882. In the movie the Earp's arrive in Tombstone in 1881 and ride past Boot Hill Cemetery. The tombstone displaying one of the most famous epitaph ever written is visible: "Her lies Lester Moore, Four slugs from a .44, No Les, No more." The problem is that Lester Moore wasn't killed until 1884. So it's impossible for his tombstone and famous epitaph to be in Boot Hill when the Earps arrived.
Continuity mistake: In the beginning, when Doc Holiday is playing poker with Ed Bailey, they tell Doc to drop his cards. He does so, and reveals a poker of queens. In a fury, Ed Bailey stands up pushing the table. When he does this, you see Doc's cup with liquor in it fall and roll off the table. Doc even watches it fall off the table onto the floor. When they show Doc again, the cup is right there where it was before, in perfect stance. Doc even drinks the rest of the liquor inside it, a little bit later on in the scene. (00:11:55)
Continuity mistake: Just prior to the actual gunfight scene as both sides have their hands on their guns waiting for something to happen, Frank McLaury is first shown wearing his hat. A few moments later he is shown by himself, looking to his right, without the hat. Then again, moments later, the hat reappears.
Continuity mistake: In the first scene when the priest, bride, and groom, etc. come out of the church you can see the priest putting on his hat in two different angles.
Revealing mistake: When Wyatt and the others leave two cowboys hanging in front of the Dragoon Saloon, you can see that neither man actually has a rope on his neck. As the one man swings around, on his vest you can see the outline of the rope going straight down into the harness that's holding him. (01:25:35)
Continuity mistake: During the fight at the O.K Corral Doc empties one of his guns into the man with the blue shirt on, then the man starts shooting through the window and Wyatt shouts "Doc, behind us." Doc Holiday immediately empties both his guns into the building without time to reload one.
Factual error: In the scene when Virgil returns to the Oriental after being shot, Wyatt and Morgan are sitting at a table eating Chinese noodles with vegetables, among which is broccoli. Broccoli was practically unknown in the United States until it began to be commercially cultivated in California in the 1920s.
Continuity mistake: In the scene where McMasters is looking through his eyeglass and telling Wyatt how many cowboys there are, there's a shot of Doc coughing with a bloody rag up to his mouth. The camera goes back to Wyatt, and when it goes back to Doc, there is blood dripping out of his mouth and all over his bottom lip and chin. In the very next shot when Doc falls off his horse, about two seconds later, his mouth and chin are completely clean.
Continuity mistake: When Doc and Kate are leaving the saloon after he stabbed Ed Bailey, as they stand in the doorway facing the people In the saloon, the light outside shows bright sun with shadows from the buildings, indicating it is mid to late afternoon. When they step outside, there is no bright sunlight and the entire street is in dusky shadow.
Visible crew/equipment: In the opening sequence where Curly Bill and gang are walking toward the church, a microphone with a furry wind sock can be seen in the lower left just before Ike Clanton passes.