When Holly gets out of the cab in the rain at the end, her hair is already soaking wet from previous takes.
When Holly first looks through Paul's window and sees the 'decorator' leaving him $300 while he sleeps, the ornate gold clock in the background reads 11:30. However, just a few minutes later, once Holly is inside the room, the clock shows 4:30. For the next five minutes, it remains on 4:30, without moving at all.
In the final scene, Paul's rain-soaked hair switches back and forth from being tussled in the wider shots to being slicked back in the close-ups.
After Holly enters Paul's bedroom through the window, stockings appear on her legs.
Paul's apartment is clearly on the third floor as known from the early scenes; yet when Paul returns home with groceries, he unlocks his apartment on the first floor.
When Holly is listening to the LP to learn Portuguese, the voice in the record speaks Portuguese with a Portuguese accent (and not Brazilian, as it should be).
Paul cites a review from The New York Times Book Review of his book; he gives the date October 1, 1956. The Times Book Review is a Sunday supplement and is dated for Sundays; October 1, 1956 was a Monday.
When Holly puts on the simple white shirt as a nightgown when getting out of bed, she turns away from Paul and it is open in the back. Some have stated here that there is a rip in the back of the shirt, or that pins have come away. That is incorrect. She is wearing a "back-button tuxedo shirt." It is designed with no opening in the front so that it stays smooth, and is put on as one would put on a hospital gown.
Towards the end, when Holly and Paul are in the cab, it can be seen that the taxi driver isn't really holding the steering wheel and that it's turning itself.
(at around 1 min) Just as Holly turns from the Tiffany's window, the camera pans left, and a crew/police individual can be seen holding back traffic on the street in the distance.
Camera shadow visible on the wall as Paul leaves Holly's bedroom, following her destruction of it.
Throughout the movie the name "José" is always said with the Hispanic pronunciation of the letter "J" (ho say), but the character is said to be Brazilian. Although Brazil has a Spanish-speaking minority, especially in the borderlands with Argentina and other nations, the nation's primary language is Portuguese, where "J" is pronounced similar to the French fashion as in Jean or Jacques.
The Tiffany salesman (John McGiver) twice refers to the company as "Tiffany's". The actual name is Tiffany & Co., and its personnel actually use either that full name or "Tiffany".
When Holly and Mr. Pereira come from a dinner party, he brings a banderilla (a Spanish and not Brazilian artifact) and says "Olé" which is Spanish rather than Brazilian Portuguese.
When learning Portuguese Holly says there are over "four thousand irregular verbs." However in Brazilian Portuguese these have all been rationalized. Holly was going to Brazil.
Holly pronounces the composer's name "BERN-steen". It should be "BERN-stine".