Continuity mistake: Truly crashes into the pond three times: first when the kids are playing in the road and she takes them home, second on the day of the picnic when she says she has nothing else to do and will go on the picnic too, and third at the end of the film when Potts finds out he is rich. In the second of these three, when Mr. Potts carries Truly from her car in the pond, the end of the ribbons on the back of her dress gets soaked in mud, but when you see her again at the beach there is no sign of the dirt.
Continuity mistake: Dick Van Dyke is trying to show his new whistle sweet to Mr Scrumptious, the sweet factory owner. His dog is tied up to a bicycle outside. When his dog hears the whistle he knocks over the bicycle whilst trying to get free and runs up the steps. In the immediate shot following the bicycle is standing up again.
Continuity mistake: During the "My little choochy face" song, the Baron's wife is seen dancing in shoes with a one inch heel. Prior to being dropped down a hatch she can be clearly seen wearing flat shoes. She subsequently appears through a side door wearing the heeled shoes.
Continuity mistake: When they are driving down the road the man driving isn't turning the wheel, but the background shows a winding road.
Continuity mistake: Chitty's front wheels are badly damaged in the crash, but are near perfect when Caractacus brings the car home.
Continuity mistake: When the car which becomes Chitty crashes in the beginning, the vent and the front left wheel become totally loose, but in the next scene where the children are playing in it, the vent and the wheel are attached.
Continuity mistake: When Jeremy and Jemima tell Mr Potts about the car at Mr Coggins' place and how Coggins told them they could have if Mr Potts paid him 30 shillings, they tell him to give Coggins the money in the morning, presumably so the junk man can't take the car. However, the next morning, they all instead go off to the sweet factory to show Mr Scrumptious the toot sweets Mr Potts discovered the night before, and it's actually not until the day after (after Mr Potts got all that money at the funfair during the night) that Potts finally pays Coggins and gets the car.
Continuity mistake: In the scene where all 4 characters are first riding in Chitty (waving at the train and just after), the two children riding in the back seat alternate between wearing hats and not wearing hats. This may have been done to conceal actor's doubles.
Continuity mistake: In the "Chitty on the water" scene, when Chitty has deployed a float her wheels become horizontal. In the far way shots, the wheels aren't moving. In the close up shots done in the studio, the horizontal wheels are spinning and there is no visible raft beneath the boat.
Continuity mistake: When the two spies try to capture Chitty by parking their open van under the railway bridge, then dropping a canvas screen down over the top so it looks like the road under the bridge is clear, as Lord Scrumptious's car hits the screen and tears through it, you can see that there is nothing parked on the other side. The van is gone. Yet the following shot establishes the fact that the trap has worked successfully; the car has gone through the screen and ended up in the back of the van.
Continuity mistake: When they are almost done singing "You Two" there is a big ripple in the tablecloth. After they finish singing and the plates are rolling down, the ripple is gone.
Continuity mistake: During Mr Potts's solo dance as the rag doll, Truly as the doll, the music box and the surrounding mirrors completely disappear, and then reappear again ready for Mr Potts's and Truly's duet.
Continuity mistake: In the scene where Mr Potts is putting the children to bed they offer him the objects from their treasure chest: a ivory tusk, "jewels" and a "crown". Near the end of the song he puts the objects back into the box but not the crown.
Continuity mistake: When Truly accompanies Mr. Potts and the children to the beach, her hair is first in a bun, and then later is worn down around her shoulders when they reach the beach. Also, the tightness or her curls vary from scene to scene while at the beach.