Continuity mistake: The licence plate of the taxi which hits Sebastian in the end changes during the shot. (01:27:35)
Continuity mistake: In the final scene where Annette is driving the Jaguar and having flashbacks, watch as she drives past lovely rolling hills and pastures. Cut to a helicopter shot of her driving the car along a New York freeway (FDR I think...) This mistake has been confirmed by the director. (01:33:35)
Continuity mistake: When Kathyrn is in the bathroom (right before the service) she puts some memocards in front of her on the sink. There's a word highlighted with an orange marker. In the next shot the card has got no marked text. The third shot it's back again. (01:29:45)
Continuity mistake: When Kathyrn and Sebastian are arguing because he won't sleep with her, he grabs the phone from her and slams it down. But when the camera shows the desk, the phone is on the opposite side from where he slammed it into the receiver. (01:12:50)
Continuity mistake: When Sebastian goes to visit Blaine, Blaine is using a scale to weigh out some marijuana. In one shot, there is a big pile on the scale, the camera cuts away. When the camera comes back to Blaine, there is a much smaller pile of marijuana. The camera cuts away and back again...the big pile has reappeared. (00:20:30)
Continuity mistake: In the final scene where Annette is driving Sebastian's car, in a close up shot she is wearing a watch, but in the next overhead shot, she is not. (01:33:30)
Continuity mistake: When Sebastian "catches" Blaine and Greg, watch when he says "After all, it is you who is bad mouthing me to Annette Hardgrove". In shots of Sebastian's face, his hand is tipping Greg's chin upwards. In shots of Greg's face, Sebastian's hand is nowhere near his face.
Continuity mistake: When Sebastian is breaking up with Annette, her pink cardigan is pulled back and the top of her bra is being revealed above her dress. In the next shot, the dress is pulled up and the cardigan pulled over.
Continuity mistake: In the end when Kathryn receives a copy of Sebastian's journal, the title page reads, "Cruel Intentions". When several moments later, just before the headmaster takes the crucifix and opens it, the camera pans across the journal in her hands, the title now reads "Cruel Inventions".
Continuity mistake: When Sebastian is explaining to Kathryn that he had the chance to sleep with Annette but he didn't, he is lying on the bed with Kathryn straddling him. Then he gets up and pushes her over. When the camera switches to a different view of her, her legs and arms are in different positions than they were before. (01:05:00)