Continuity mistake: During Marty's drive to the bogus address, when he is done speaking with Monty, just as he says, "Wolf out!" he pulls the phone wire and the earpiece actually pops out of his ear, but in all of the following shots that earpiece is still in his ear. Since the super-glued earpiece is one of the main plot points, this is bizarre to say the least. (00:44:25)
Continuity mistake: In the scene where Jason's parents arrive at the airport in Los Angeles his mother is wearing a brown jacket. It remains brown until the scene where Jason meets his parents at the set and his mother's jacket is maroon. While she has more than enough offscreen time to change jackets, she does not have a jacket to change into (they are driven straight there) and no reason to change the jacket.
Continuity mistake: Before and after Marty's appearance at the birthday party, his car's five-point star hubcaps are visible in close-ups. After Marty's encounter with Masher, when the car is towed its hubcaps are entirely different. (00:44:50 - 00:50:25)
Continuity mistake: When Jason leaves Marty's limo he exits from the left side of the limo, on the driver's side. In the next exterior shot, he is leaving from the right side of the limo, the passenger side, which is the side Marty sits on. (00:15:47)
Continuity mistake: Jason and Kaylee arrive in LA on Thursday, and phase one begins Friday morning, but during 'phase one: surveillance day', when Jason and Kaylee are at the stunt demo, Jason looks at Marty's iPAQ PDA and the date reads Sunday, June 4th (stunt demo noted between 12:30 and 1:30pm). Yet, when Vince, the stunt coordinator, tells Marty that he's taking the next day off (day of 'phase two') to take his granddaughter to a birthday party, the clown invitation notes July 28th as the day of the party. Then, on Saturday 'phase two: the take down', when Jason is seated at the bus stop he looks at Marty's PDA and the date reads June 22nd, the day of the 'Whitaker and Fowl' premiere and party. Go figure... (00:35:50 - 00:52:40)
Continuity mistake: The morning of 'phase two: the take down', when Marty awakens at 6:45, in the close-up he lifts the snug ice-pack mask to his forehead, but in the next wideshot the mask has vanished though he hasn't touched it. (00:39:40)
Continuity mistake: Just after Jason's parents leave, when Rudy pulls up to pick up Janie the front passenger window is rolled up, but when Janie and Rudy turn to head back to his ZR-2 and he says, "Peace out, little G," that window is rolled down. (00:15:10)
Continuity mistake: At the premiere of Marty's failed movie, he is asking the president if he can explain his "breakthrough" on Big Fat Liar. The president raises his hand, and says "One chance, Wolf, that's all I'm giving you." It remains raised until two shots later (on Marty's line "strap on your seatbelt because you are about to be blown away,"), when it is suddenly resting at his side.
Continuity mistake: The degree of blueness and orangeness of Wolf's skin and hair keep changing. Right before the first birthday party, he has bright orange hair. Yet when he leaves the birthday party, his hair is a duller orange. I don't think that hair dye wears off that fast.
Continuity mistake: When Marty is talking to the studio's president about his 'incredible breakthrough' about BFL, Monty has her head leaned up against a chair. Marty continues talking when the camera cuts to a close-up of Monty. With no time in between shots to move her head, her head moves about 6 inches away from the chair.
Continuity mistake: At the very end, during the credits of Jason's 'Big Fat Liar' premiere, you can see Jason's mom over his shoulder wearing a spaghetti strap dress with a shawl around her shoulders. The shawl moves on and off her shoulder between shots.
Continuity mistake: When Jason writes his paper, we see the handwriting of the title "Big Fat Liar", etc. Later, in the limo when Marty finds the story and when Jason is in Marty's office, we see the paper again and the handwriting differs.
Continuity mistake: Near the beginning, when Jason is done writing his paper he staples it. When he and Marty are in the limo, the pages are not stapled.
Continuity mistake: When Marty Wolf is washing his hair, before he dyes his beard you can see it is already a slight tint of orange.
Continuity mistake: When Marty is done speaking to Monty while driving to the bogus address, after he pulls on the phone wire, in the shot from his car's interior we can see that the wire actually ripped, but after nearly colliding with "grandma" the phone wire is again intact. (00:44:30)
Continuity mistake: During phase four, when Marty opens the passenger door of Jaleel's speeding car he wears a baseball cap, but in the next wideshot his head is bare as he hits the ground and rolls - the baseball cap is gone, it didn't fall off. After a close-up of Jaleel, it cuts back to Marty and the baseball cap is back on his head just before it falls off, as he continues to roll. (01:06:40)
Continuity mistake: Just after blue-Marty ends the call with Monty, in the shot facing Marty's car from the POV of the old woman's car just as Marty swerves to avoid her, Marty's window is rolled down, but in previous and following close-ups that window is rolled up. (00:44:30)
Continuity mistake: When Jason writes the paper and then staples it, there are neat/short bits of paper at the side edge, where the pages were torn from the notebook (also visible after he slams into Marty's limo). Then, when Marty finds the paper, the entire left side edges are filled with much longer extra bits of paper. (00:06:50 - 00:09:55)
Continuity mistake: When Marty enters the home of the birthday party, there is a large area rug lying directly in front of the set of double French doors. In following shots, this large rug has moved closer to the front door (before all the kids jump on him) - note the table beside the French doors. (00:45:00)
Continuity mistake: When Marty Wolf pulls up behind "the Masher", an old lady hits Wolf's car and pushes it into the Masher truck. The old lady drives off while insulting Marty. The Masher drives around to crush Marty's car. When it cuts to Marty watching the Masher drive towards him, you see the old lady's car behind his again.