Gossip Girl Mistakes highlights storyline bloopers, visual slip ups in the show, or things that are possibly retconned.
SPOILERS IN ARTICLE AND COMMENTS.
- Nate's haircut noticeable changes from longish at Eleanor's party to trimmed when he's jogging with his father Howard and back to long when at lunch with Blair (Pilot).
- Chuck takes the bus with Nate to school, and Dan is also onboard. However in every episode after, Chuck has his own limousine and Dan is shown walking to school (Pilot).
- The entire Waldorf apartment is completely different to what it looks like in every episode after. Blair's bedroom is also a different color and has different furniture inside (Pilot).
- Blair's mother, Eleanor, is played by Florencia Lozano in the beginning but is portrayed by Margaret Colin after and for the rest of the series (Pilot).
- Chuck speaks of his mother as if she's still alive, but it's later revealed that she is deceased (Pilot).
- The Gossip Girl website is shown to be entirely different from every other episode (Pilot).
- Six minutes in, Jenny is laying on her bed with her legs down but when you see her from behind, her legs are in the air (The Wild Brunch).
- Through the first few episodes, most everyone changes cell phones. At one point, Serena drops her cell phone in a trash can but is seen with it in episodes after. (The Wild Brunch).
- Serena tells Dan her father went to Harvard University (Poison Ivy) but later tells Blair her father went to Columbia University (Belles de Jour). However, this could be possible because she also mentions he went to Columbia for med school. Therefore, he could have gotten his bachelor's at Harvard.
- Hazel's mother's closet, where Jenny steals the dress from, is the same closet that is later shown as Blair's (The Blair Bitch Project).
- Georgina removes the battery from Dan's cell phone and throws it away (Woman on the Verge) but he uses it the next day to call her (Much 'I Do' About Nothing).
- Chuck mentions he lost his virginity to Georgina (Woman on the Verge) but then he says he lost his virginity to an Italian au pair (Gone with the Will).
- Lily's birth year is revealed to be 1969 via her passport. Valley Girls is set in 1983, when Lily should have been fourteen. However, she drives a car, which would be illegal due to her age.
- When Bart's will is read, Chuck makes a comment about Bart's disdain for Chuck wearing so much purple (Gone with the Will) but later he says he wears purple because Bart loved it (The Sixteen Year Old Virgin).
- Olivia promises Dan she'll be back the following fall but she never actually returns (The Last Days of Disco Stick).
- Blair and Serena walk through the Columbia campus and Blair is holding different colored folders. The camera switches to Serena and when it goes back to Blair, the folders are in a different order (Goodbye, Columbia).
- Jenny steals Serena's sim card from her phone, but later she still gets Gossip Girl blasts and uses it just fine despite the missing sim card with all her information (The Witches of Bushwick).
- Ben texts Juliet while he's in jail, which really wouldn't be possible (War at the Roses).
- When Blair and Dan decide to email Gossip Girl asking for help on finding Juliet, they wait for the email together and read it when she does. It's questionable how Dan could have emailed Blair as Gossip Girl with her right there (The Townie).
- When Charlie (Ivy) has coffee with Serena, they laugh about the time they spent on Lily's ex's yacht (The Kids Stay in the Picture), but later Lola insists she never met or even knew about any of the Van Der Woodsen's.
- When Serena calls Max, her phone is briefly shown to just be on the home screen and not on an actual call (Rhodes to Perdition).
- Nate talks to Chuck in the kitchen and suddenly becomes swollen for the rest of the episode (The Princess Dowry).
- In the flashback, Blair's apartment is shown to be the way it was through the whole series and nothing like it was in Pilot (New York, I Love You XOXO).
- In the flashback episode Valley Girls, Lily is portrayed by Brittany Snow, who has bright blue eyes. However, Kelly Rutherford has hazel eyes.
- Headmistress Queller is played by two different actresses, Linda Emond from School Lies to In the Realm of the Basses. And by Jan Maxwell from You've Got Yale! to The Wrong Goodbye.
- Whenever an iPhone rings onscreen the "Slide to Answer" isn't animated, meaning it is a screenshot and not a real call.