Cecily Brooke von Ziegesar is an American author best known for the young adult Gossip Girl series of novels.

Gossip Girl is an American young adult novel series written by Cecily von Ziegesar and published by Little, Brown and Company, a subsidiary of the Hachette Group. The series revolves around the lives and romances of the privileged socialite teenagers at the Constance Billard School for Girls, an elite private school in New York City's Upper East Side. The books primarily focus on best friends Blair Waldorf and Serena van der Woodsen, whose experiences are among those chronicled by the eponymous gossip blogger. The novel series is based on the author's experiences at Nightingale-Bamford School and on what she heard from friends.