he fifth and final season of 90210 was announced on May 3, 2012, that The CW renewed 90210 for a fifth and final season. On May 17, 2012, it was announced that the show's fifth and final season would be moving back to Mondays at 8:00pm Eastern/7:00pm Central followed by the sixth and final season of Gossip Girl at 9:00pm. The season premiered on October 8, 2012.The fifth and final season of "90210" follows the group from West Beverly kids as they navigate life after high school. Their journey into adulthood will find them heading in different directions while trying to keep the same closeness that worked so well for them in high school. Coming from a world of glamour and privilege, with endless possibilities in front of them, anything can happen. All in all, it's just another day in the world's most famous zip code.

90210 went on its mid-season break on December 10, 2012 and returned on January 21, 2013 at a new time slot of 9:00 pm, one week after The Carrie Diaries premiere, which took its original time slot of 8:00 pm.

On January 13, 2013, the President of The CW Mark Pedowitz stated that although 90210 doesn't have a season 6 renewal in place, the show would most likely be back next year due to him being a "big believer in giving fans a very satisfactory conclusion" for long-running shows. In spite of this, in late February it was announced that the fifth season would indeed be the final season of the show, with the series finale airing May 13, 2013.

Overview from themoviedb.org