The first season of 90210, an American television series, began on September 2, 2008. Gabe Sachs and Jeff Judah are executive producers for the first season, after original producer Rob Thomas dropped out to focus on other projects. The series premiered to 4.65 million viewers, and broke records for The CW at the time, becoming their highest rated premiere in viewers and in Adults 18–49 with a 2.6 rating. On September 22, 2008, after airing just four episodes, the network gave the series a full-season order of 24 episodes.

The second season of 90210, an American television series, premiered in the U.S. on September 8, 2009 and ended on May 18, 2010. The season picks up at the end of summer after the events of last season's dramatic prom party. Rob Estes, Shenae Grimes, Tristan Wilds, AnnaLynne McCord, Ryan Eggold, Jessica Stroup, Michael Steger, Jessica Lowndes, and Lori Loughlin all return as series regulars from season one, while Dustin Milligan was released from his contract for "creative reasons".