Continuity mistake: When the family arrives at the Redondo Suites Hotel, they pull into the middle of the parking lot. When the funeral home van is there, the van is in an entirely different spot with bushes at the front bumper. Then, when they are leaving, the van is back in its original space. (01:14:00 - 01:19:00)
Character mistake: When they arrive at the motel, the mother says that the grandpa is in room 13, but when he opens his door it is room 208.
Factual error: The family passes an exit for Carefree Highway. This is an exit off I-17 a few miles North of Phoenix. At that point they would be about 10 miles from Scottsdale. Yet they drive all day and that night they are still within scooter range from Scottsdale.
Continuity mistake: In the Little Miss Sunshine pageant there is a girl who, in the talent competition, does a dance in a cyan-colored uniform-type costume. Her act is before Olive's, which is the very last act, however after the girl's act, she can be seen in one shot being led towards the stage and in another having makeup put on, both times in the same costume. Neither of these should be happening if she has already done her act.
Continuity mistake: During the backstage pep talk, the clasp on the Mom's necklace changes position.
Revealing mistake: In the scene where the grandfather has passed away and the family is at the hospital, there is a shot where the family steals his body and pushes it out a window. At one point in the next shot, when the family is carrying "him" to their van, the sheet moves and it's obvious the cast is carrying a bunch of pillows covered in a sheet. This also is obvious from the ridiculous way the "body" is laying on the bed prior and folds up when the cast picks "him" up and hoists "him" out the window.
Visible crew/equipment: In the scene where Olive is beginning to do her dance at the Little Miss Sunshine contest, when the camera starts moving when she walks forward in the shot at her front, look at the curtain behind Olive's left shoulder. A camera shadow can be seen moving with Olive.
Continuity mistake: In the mad rush to get to the hotel, the family gets off on the exit and is trying to decide what to do. During this time, the camera angle changes several times. During this change, the traffic behind them disappears, and reappears between shots. Most noticeable is a semi that vanishes and reappears.
Factual error: When the family is leaving Albuquerque, there are saguaros along the highway. Contrary to popular belief, saguaros don't grow anywhere in New Mexico.
Other mistake: In the scene where the family is almost at the hotel, Richard asks Frank what time it is. Frank looks down (as if he is looking at his watch) and says "Two fifty-nine." Frank is not wearing a watch in any scene in the entire movie, especially given the fact that both of his wrists are bandaged from his suicide attempt.
Visible crew/equipment: When the family is trying to load the body of Grandpa into the VW, the shadow of the camera can be seen multiple times at the bottom of the frame. It shows up most obviously on uncle Frank's shirt.
Continuity mistake: During the scene where the whole family is seated around the dinner table (before the road trip), the popsicle box in front of Steve Carell keeps changing angles.
Continuity mistake: During the dinner scene at the beginning of the movie, there is a round polystyrene pot on the table that moves between shots. In the long or close up shots, it is right in front of the Popsicle box, whereas in the side shots, it is in the centre of table, quite a distance from the box.
Continuity mistake: When Olive tests Dwayne to see if he is colorblind, she is holding the pamphlet, showing him the letter in the circle. In the next shot, Dwayne is holding the pamphlet, and in the shot after Olive is holding the pamphlet again.
Continuity mistake: When Olive approaches her brother as he sits in the field, his legs are crossed but then uncrossed when the camera angle changes.
Deliberate mistake: At the very end when they are all running to get the car started, the boy is the last to hop in. In the first scene, he is well along side the car, but in the very next shot he is farther again. In the last shot, he is closer to the door and finally gets in.
Continuity mistake: In the scene where Olive is giving her brother the color blindness test, he writes something on his note pad and gives it to Olive. In the next shot, the brother has the notepad and then the following shot, Olive has the notepad.
Continuity mistake: When Dwayne stands up in the fields to walk back to the VW with Olive, there is dirt and grass on his rear end. As they reach the top of the hill, there is no dirt at all.
Continuity mistake: When Dwayne has his outburst after discovering that he is color-blind, observe the wheels of the VW stopped at the edge of the highway. In close shots the tires are next to a raised curb, while in distance shots the full tire is visible, right down to the point where they touch the pavement, indicating no raised curb.
Other mistake: At the end of the movie the VW bus still has the broken clutch and horn as evidenced by the family needing to still push the bus to get it going (and the horn continuing to sound). But they had time to fix the sliding door so why didn't they just fix the broken clutch/horn as well? Unlike when they were driving to LA, they weren't on any time crunch going home. They could have either fixed the van or just got a rental to drive home.