Continuity mistake: When William takes Anna back to his flat, after the orange juice incident. His shirt is stained, she comes into the flat and changes. Then she leaves. When she returns to get her books, his shirt is still stained but after she kisses him the stain is gone. An impressive kiss...
Revealing mistake: In the scene where they are all having a farewell dinner at Tony's restaurant. At the end of the meal they are all scattered around the restaurant, the camera is on Bella and Honey and in the background, outside the restaurant, 4 extras walk past, 3 at the front and one behind. The next shot is at the window where Max and William are sat, again the 4 extras walk past in exactly the same order and positions. They are the same people because one of them has a pink top on and you see that twice.
Continuity mistake: After William leaves the movie set, in the next shot he goes back to the book shop. Seen through the window is the table with the books and globes. Then when Anna is standing near the window, we see that there are completely different kinds of books on the top shelf now.
Revealing mistake: In the scene where Will and his friends are driving to catch Anna at the press conference, Spike jumps out of the back of the car to halt traffic and let their car through. When he closes the back door, the sound effect of a slamming door is loud, but the door doesn't shut - you can see it bounce back up.
Continuity mistake: When William initially walks into his bookstore after he takes the mail from Martin, on the bookcase he approaches to his right we see close-up some of the books on three shelves, one of which says 'Siberia', and also the two small posters, the bottom says 'Mukiwa' and the top says 'Lonely Planet', tacked to the side of this bookcase. When Anna browses that same bookcase, she looks at the book 'My Turkish Delights'. The books that are on the shelves of the bookcase, and only the top poster that is tacked to the side are now completely different.
Continuity mistake: In the 3-shot sequence where Honey is opening her birthday gifts, the shots show the following: 1. Hugh Grant puts a necklace on Honey and she is wearing the hat; 2. She has just opened the hat and is not wearing the necklace; and 3. She is wearing the hat and no necklace. In the following sequence (the competition for the brownie), she is wearing the necklace and no hat.
Continuity mistake: In the scene just before Anna goes into the bookshop with the painting there is an outside shot of the building. In front of the school you can see the woman kneeling down in front of a child but also if you look through the window and door of the shop you can see Will walking in wearing a blue shirt. In the very next scene he is sitting at his desk wearing a pink shirt.
Continuity mistake: In the scene where Julia Robert's character first goes to Hugh Grant's character's flat, there's a chalkboard that's telling Spike to clean up. It's quite small writing, but in a close-up of Hugh Grant when he's directing her upstairs it's clearly larger. It then goes small again until she comes downstairs, when it goes large and stays that way.
Continuity mistake: Anyone familiar with Notting Hill will know that the rooftop terrace scenes with Spike and William and later with William and Anna, were not remotely in the same neighbourhood as William's flat with the infamous Blue Door. The rooftop scenes were filmed most likely on rooftop between Ladbroke Grove and Stanley Gardens, while the flat with the Blue Door is located on Westbourne Park Road.
Audio problem: Anna is at Will's place to take refuge from the press. In the morning he opens the door, unaware of any trouble, and faces a yelling and hooting crowd of reporters. Then he shuts the door, and you don't hear a thing, although the door looks anything but soundproof.
Continuity mistake: In the scene just after Anna opens the door and all the photographers are outside, Spike walks to the front door in his grey underwear. Just before he opens the door the underwear is covering only one butt cheek (his left). The next shot outside the house the underwear is adjusted and covers both butt cheeks but then when he enters the house and is checking himself out in the mirror, his butt cheek is exposed again.