Maureen Vanderbilt (nee Stewart) is a recurring character in the Gossip Girl TV series during the show's second and third season. Maureen is Tripp Vanderbilt's wife, whom he married during the show's second season. The third season shows a more complex character of Maureen Vanderbilt, displaying a manipulative and calculating nature rather than her more unassuming and obedient exterior. She makes use of her status as a politician's wife during Tripp's campaign and is fiercely protective of him and his career. Holley Fain portrays Maureen Vanderbilt.
Maureen is first introduced at the Vanderbilt Family reunion as Tripp's fiance. During a conversation with Maureen at the reunion, Vanessa discovers that Tripp originally wanted to be an archaeologist and that their grandfather, William Vanderbilt persuaded him to take a career path in politics. Maureen shows an interest in her fiance's career path.
A day before her wedding, she has the Whitney Junior Committee aiding her wedding preparations and gives Blair the bad news that she had been replaced as a bridesmaid. The news would later drive Blair to scheme for William Vanderbilt. Maureen is present when Nate publicly criticizes his grandfather during a party at the Vanderbilt Compound.
Tripp and Maureen return to the third season a married couple and takes a deep interest in her husband's political career.
During the week of elections, Maureen is present at her husband's campaign and during the Vanderbilt Election party where her husband had growing concerns over his political career, fearing that the fake drowning incident could cost him his political career. When Nate takes the fall for his grandfather and Tripp by publicly stating that he set-up the fake rescue, Tripp wins the election moments after Nate's speech and happily embraces Maureen. Later, Maureen joins William for a drink during the election party and states that she created the fake drowning incident so that Tripp could win the election. She also tells William that she is glad that he won't be taking control of Tripp's political career, revealing her manipulative and calculating nature. William replies that he will tell Tripp of her scheme but Maureen tells him that his credibility is short and that Tripp would believe her more than him.
During Thanksgiving, Lily Humphrey spots Maureen before they cross the street wearing identical coats. Lily, hoping to see more of her Serena since her job takes her away from time with the family, invites a reluctant Maureen and Tripp for Thanksgiving. Maureen then becomes suspicious of Serena and Tripp. Nate, angry at Tripp, shows a video of Serena and Tripp kissing in an elevator to Maureen, whose suspicions are confirmed. During Thanksgiving, an angry Maureen confronts Serena and Tripp and shows them the video. Lily incidentally sees it and leaves with Serena following her. Maureen leaves the dining table but comes back for her coat during the evening. Unfortunately, Maureen takes the wrong coat, one that contains the letter from William van der Woodsen for Lily, and reads the letter, smiling as the elevator closes.
When Serena and Tripp leave the city for their country home, Tripp lies to Serena about meeting his grandfather but is in fact meeting with Maureen to discuss the future of his political career. Maureen assures him that he'll find a way to keep his career and for her to keep her marriage and status and tells Tripp that she'll got to Serena to discuss an agreement. Serena is surprised to see Maureen in the Vanderbilt country home and asks her to leave. Maureen asks for a civil conversation and begins her agreement offering Serena the status as a mistress to Tripp, condescending. She applies a subtle analogy by comparing their situation to that of Jackie Kennedy and Marilyn Monroe where Maureen is in the same position as Jackie and with Serena as Marilyn. Serena angrily refuses the offer and decides to leave.
Following the car crash after Tripp and Serena return to the city, Tripp attempts to visit Serena at Nassau Grace Hospital only to be barred by Nate, angry at what he did to Serena and threatening to call the sheriff's department. Maureen enters the scene, silences Tripp with a cold display of her disdain for him and tells Nate that their grandfather has their back to keep Tripp's career and gives Tripp an alibi saying that he was with her all night. Nate decides not to tell the cops and Maureen leaves with Tripp. When Nate punches Tripp asking if he could help him visit Serena, Maureen looks on and does nothing to help him.