Continuity mistake: In the scene where Scarlett is talking to Ashley about owing the carpet bagger 300 dollars right before Ashley kisses her you can see a definite change. Ashley has different dirt on his face and Scarlett's dress looks lighter. Her hair is also loose in different places.
Factual error: Scarlett is seen walking on the main street on the way to the hospital. You can clearly see a light bulb in one of the street lights.
Revealing mistake: In the scene where Ashley is brought back wounded from the raid where Scarlett's husband Mr Kennedy was killed, Melanie grabs a gas lamp to follow the man carrying Ashley to the bedroom and you can see an electrical cord hanging down from it.
Other mistake: The credits for the Tarleton brothers in the opening credits have the twins switched with their actors. George Reeves doesn't play Brent, he plays Stuart. You know this because in the opening scene the two boys are talking about the party and asking Scarlett for dances, and George Reeves points at his brother and calls him "Brent."
Continuity mistake: The shadow scene in which Scarlett and Melanie care for the wounded in the Atlanta hospital was filmed with two doubles. Since Leigh and de Havilland were standing at the wrong angle to cast the shadows, two stand-ins were positioned in front of the high-intensity light. The shadows of the doubles were reflected on the wall behind the stars, and the result was a stunning visual effect. Yet upon a closer look, the gestures of the stand-ins are not totally synchronised with the movements of the stars.
Continuity mistake: When Scarlett is attacked in the woods on a bridge while on her way to the lumber mill the buggy very nearly goes off of the bridge backwards. Then Scarlett faints, but when the camera returns to the full shot of the buggy, suddenly it is squarely in the middle of the bridge and in no danger at all of falling over the edge.
Continuity mistake: In the scene showing guests arriving at the Wilkes' barbecue, you see buggies and carriages driving through the front gates and up the drive toward the Wilkes' home. The carriages clearly create shadows on the ground, but not on the stone pillars of the gates. This is because when the movie was filmed, there were no actual gates. The gates were later "painted" into the frame. Proving someone forgot to "paint" shadows onto the pillars.
Continuity mistake: During the burning of Atlanta scene, Rhett and Scarlett are escaping in a wagon. The horse stops, spooked by the fire, so Rhett throws Scarlett's shawl over the horse's eyes. The mistake is that as soon as Rhett grabs the reins, the horse throws off the shawl, and suddenly no longer is afraid of the fire.
Continuity mistake: While our protagonists flee from the burning Atlanta the carriage stops. A bearded soldier walks by carrying another man. A few moments later the camera focuses on a young man who collapses and is being picked up by exactly the same guy who was carrying him already. The mistake wouldn't be as pronounced if it weren't been one of the few instances where action by extras is highlighted.
Continuity mistake: When Rhett stops the carriage on the bridge at the turn for Tara, he pulls the brake to keep the carriage from moving. When Scarlett drives off in the carriage, she does not release the brake.
Revealing mistake: When Scarlett finds Twelve Oaks completely destroyed, the carriage in the background is not real. As Scarlett walks toward the staircase, both the carriage and Prissy are not real, it is just a picture that has been painted to make it look like they are sitting there.
Continuity mistake: When Scarlett is attacked in the woods, Big Sam drives her carriage out of danger. When the scene cuts to a far shot of the carriage driving through the woods, Big Sam is no longer with her. She is driving it by herself.