Continuity mistake: When Serena is saying goodbye to Dan, rain is pouring on the angle focusing him, but not on the angle focusing her. This changes back and forth.
Continuity mistake: Blair exits the church and talks to Chuck inside a limo. On the reflection on the car's windows she has her sunglasses on, but on the close-ups she doesn't.
Hi, Society - S1-E10
Continuity mistake: When the episode starts, Serena and Blair are walking down the street. The people behind differs between the close-ups and wide angles.
Continuity mistake: When the family is breakfasting, the knife on the mother's dish appears and disappears between shots.
Blair Waldorf Must Pie! - S1-E9
Continuity mistake: Lilly finishes her Thanksgiving meal and takes a glass to her lips. A frame later her arm is down.
Much 'I Do' About Nothing - S1-E18
Continuity mistake: When Nate and his dad stop jogging and chat, dad's head position doesn't match between the front and opposite angles.
Blair Waldorf Must Pie! - S1-E9
Continuity mistake: At the end of the episode, while Dan and his dad are walking, the number of people behind have no continuity between the wide and close-up angles.
Continuity mistake: In season five, when Blair is in the therapist's office with Chuck, she states that her dad left when she was fifteen. However in Blair Waldorf Must Pie in season 1 it shows that Harold was still with them last thanksgiving, when Blair must have been 16, because her birthday is before thanksgiving.
Desperately Seeking Serena - S1-E15
Continuity mistake: When Nate and Vanessa kiss for the first time, two lighting screens are reflected on the glass door.
Continuity mistake: When Dan and Jenny are discussing what Rufus and Lily are doing in Boston, Jenny picks up her coat and starts straightening it out before putting it on. The shot changes and she has instantly moved 90 degrees clockwise and is now seen removing her coat. When shot changes again she is suddenly back to her original position and has resumed putting on her coat like she was doing in the first place. (00:01:52)
Desperately Seeking Serena - S1-E15
Continuity mistake: When Dan is going to Serena's hotel room to find out why she haven't gone to the exam, he talks with her in front of the door. His hands are on Serena's neck, but the hand moves between shots,and is under Serena's hair. (00:36:55)
Continuity mistake: When Blair is walking between her two minions, she is holding green files and Zoe, the girl to the left (her right), is holding red files. After Serena enters the scene, the shot changes and Blair is now holding red files, while Zoe is holding the green files. (00:01:22 - 00:01:48)
The Lost Boy - S3-E3
Continuity mistake: Before Chuck arrives at Sotheby's, Nate is walking down the street. There's no continuity with the passers-by behind. Check the woman in black with a pearl necklace. She quickens her pace and overtakes him, but in following shots she is still walking behind him.
Continuity mistake: After Jenny makes a peanut butter and jelly sandwich, she leaves the tops off. In the next shot you see the peanut butter has its top on and in the next shot, both the peanut butter and jelly disappear as she sits by Dan.
Continuity mistake: Right before Eleanor goes out to take her bow, she hands her badge to Blair. Then when she's first seen walking down the runway she has her badge on. In the next shot the badge is off. (00:37:05)
Summer, Kind of Wonderful - S2-E1
Continuity mistake: During the White Party an African American person standing right next to Chuck appears and disappears between shots.
