Continuity mistake: Ben-Hur places his crown on a table when he visits the fallen Messala, but upon returning the table and crown are gone. (00:36:35)
Continuity mistake: When Rick Nelson tells Angie Dickinson to throw the plant pot through the window to distract the gunmen who threaten John Wayne he seems to have had a hair cut between scenes as his sideburns are halved by the time he reaches the street and grow again later.
Continuity mistake: It is supposed to be night when Joe slips out of the hotel, but a daytime sky is visible.
Continuity mistake: After the villain (Thayer David) kills a duck, a boulder begins to move and brushes the side of his right leg as seen in a close-up and both legs can squarely be seen as he is standing beside the rock. The scene changes to a stunt-man who has his left-side towards the camera and this time his right leg is closer to the boulder which pushes him over a ledge. (01:50:35)
Continuity mistake: In the scene where the two kings are fighting, one of them pulls a swordfish from the table and after they calm down sticks the fish in his belt. In the next shot the fish has disappeared.
Continuity mistake: During the split screen scene with Doris and Rock in the bath tubs, the amount of soap suds on Doris' foot and leg is less in the close ups than on the long shots.
Continuity mistake: When we first see the Colonel reading a newspaper the headline on the page he is reading starts with the word "Birmingham", but when the camera angle changes it reads "Fontwell Park".
Continuity mistake: When Molly (Sandra Dee) grabs the letters she had hidden in the suitcase under the bed, her dress is still unzipped in the back. After ranting at her mother for having read the letters, she throws them into the fireplace, only now her dress is completely zipped up.
Continuity mistake: In the opening scenes, the panoramic view of the Larkin homestead shows Lorenzo's "Gummint" Ford sitting with its hood up, days before he has been assigned to the case.
Continuity mistake: The car is out of gas, and Sylva Koscina gets impatient. As the shot changes, Walter Chiari's arm is on top of the car door (it wasn't in the first shot) and Dorian Gray crosses again her arms on top of the bag - assuming the same pose she already had. (00:17:00)