Incorrectly regarded as goofs: Mary's glove appears to darken in the close-up when she reads the advertisement to Mr. Banks, due to the lighting.
Revealing mistakes: During the beginning of the "I Love to Laugh" sequence, when Uncle Albert says, "Loud and long and clear," his left hand goes transparent into the background. (From the 40th anniversary edition)
Continuity: Jane and Michael switch sides while they are holding Burt's hand when he walks them home.
Continuity: After Mary Poppins powders her nose black, her face in the next scene is clean again.
Revealing mistakes: Obvious stand-ins for Jane and Michael when Mary Poppins, Bert and the children step onto a cloud which wafts them back down after exploring the rooftops (just before the "Step in Time" number).
Continuity: When Mary Poppins is tidying the nursery, the pictures straighten, but in the next shot they are still crooked.
Continuity: Mr. Banks tears Jane & Michael's advertisement into eight pieces. Only eight pieces of paper go floating up the chimney, but at least twice as many are shown coming out of the top of the chimney.
Crew or equipment visible: When Mary and the children are sliding down the stairs you can see the equipment rolling along with them.
Crew or equipment visible: When Mary and the children are sliding down the stairs handrail as they go in front of the maid, part of the trolley is clearly visible on the left side of the boy.
Errors in geography: The robin that lands on Mary's finger in the "Spoonful of Sugar" sequence is an American, not British, robin.
Crew or equipment visible: When Mary first turns from the window with the singing bird perched on her fingers, the cables operating the bird are visible on the back of her hand.
Revealing mistakes: When Mary and Bert are dancing with the cartoon penguins, you can see Bert's legs and some of the "real" scenery through the cartoon penguins in some shots.
Revealing mistakes: When Mary Poppins pops out of the Banks's chimney, a cable supporting her can be seen against the sky.
Revealing mistakes: During the "Supercali..." song, when Bert and Mary sing "The biggest word you ever heard and this is how it goes..." Mary's head becomes slightly transparent and you can see the animation behind her. This goof might only be on the remastered 2004 DVD version.
Continuity: Bert places his hat inside the chalk drawing under a banner that reads, "Contributions Welcome" but after the rainstorm, his hat is underneath the drawing.
Continuity: During "Feed The Birds", Mary shakes the Cathedral Globe, and the birds flutter about. Less than five seconds later, the globe appears unshaken.
Continuity: In the opening credits, Mary is shown in a close up powdering her nose while sitting on a cloud. Her carpet bag is on her right and her umbrella is on her left. In a long shot, immediately after (which is animated) the carpet bag and umbrella are not present.
Continuity: Just before walking on the stairs made of smoke, they are walking single file on a rooftop in the following order: Mary, Jane, Michael, Bert. In the next close up shot, they are not in a line. They are in a group and Michael is in front of Jane.
Continuity: When Bert traces Mary's shadow on the sidewalk, the sunlight obviously comes from behind of Mary. However, when Bert stands up to greet Mary, the sun shines frontally into her face.
Factual errors: The two Robin parents building their nest outside the children's bedroom window are both male.
Audio/visual unsynchronized: When Michael is locked in the closet while cleaning the nursery, the door opens for a second and you hear him yelling, "Let me out!" but his mouth doesn't move.
Revealing mistakes: When the penguins bring Mary and Bert menus, the menus are pink. A moment later, Bert's menu is bright purple.
Revealing mistakes: The second time that all the Banks's furniture is moved by Admiral Boom's cannon, you can see a vase sitting on a column rock back and forth, and then be pulled back to its original position by a string.
Continuity: When Bert is dancing with the penguins and he pulls down his pants so he looks more like a penguin, the area between the waistband and leg split becomes much longer and the legs becomes shorter. When he pulls them up again, they go back to normal.
Continuity: During the "vote for women" scene, Mrs. Banks places a sash that says "vote for women" on Katie Nanna. First the words are on her right side, next shot on her left side, final shot back on her right side.
Revealing mistakes: During the 'Step in Time' number when the chimney sweeps pop out of the chimneys, in one scene all three sweeps are seen coming up behind the chimneys and not out of them.
Continuity: When Mary uses the tape measure on herself, she holds the tape horizontally to read it, however the close up shows the tape vertically with the words oriented that way.
Continuity: When Uncle Albert, Bert and the children descend from the ceiling, they land on chairs. In the next shot, they are on the floor.