eason 2 featured 25 episodes and began airing on September 1, 2008 starting at the end of the summer instead of the more conventional start in the fall along with larger TV networks. The season concluded on May 25, 2009. The season premiered with 3.43 million viewers,^[9] similar to the first season and ended with 2.23, lower than expected.

The second season mainly explores the senior year of most of the characters, the continuity of their new found relationships, their final encounter with "Gossip Girl", and their attempts to get into college. The first couple of episodes feature part of the summer vacation, respectively week before the start of the school year. The role of "Gossip Girl" is slightly decreased. She continues to run her blog, but she keeps the ultimate information for herself, sending it in the final episode as the last blast, where Serena decides to find out who "Gossip Girl" really is, but ultimately fails.

The second season also focuses on Blair and Chuck, who were labeled "the heart of GG" by People magazine.^[10] At first, both characters negate their feelings for one another, and go through random schemes and manipulations. After all the games are done, both of them eventually say "I love you" to each other. Other storylines include Blair's attempt to enter Yale University; the death of Bart Bass which proves to be a very bad influence on Chuck and the exploration of his involvements; Dan's transformation from outsider to insider and his relationship with Serena's teacher Rachel Carr; Serena's relationships after breaking up with Dan; Jenny's career as fashion designer and her rebellions which ultimately ends with her becoming the next Queen Bee; the end of Nate and Chuck's friendship and Nate's friendship with Dan; Nate's family problems which continue to grow and affect on his new found relationship with Vanessa; Rufus and Lily's relationship after Bart's death, their engagement, and revelation that they have a son; and Serena's involvement with Poppy Lifton, a secretive socialite that tries to steal money from Serena and her friends which ultimately leads to the return of Georgina Sparks, who claims to be changed but eventually decides to get revenge on Blair.

The penultimate episode of the season, "Valley Girls", was a backdoor pilot for a Gossip Girl spin-off series also titled Valley Girls. The series was set in 1983 and chronicled the teen years of the Gossip Girl character Lily van der Woodsen.