James Cameron's Avatar franchise is a planned series of science-fiction films produced by Lightstorm Entertainment and distributed by 20th Century Studios, as well as associated computer games and theme park rides.
The first installment, Avatar, was released on December 18, 2009 and is the highest grossing film of all-time. The planned series was announced by 20th Century Fox on December 11, 2009, one week before Avatar was released to theaters. 20th Century Fox has confirmed the series on January 15, 2010. Note that the sequels only have working titles as of yet and they will most likely be given different names closer to the release.
Like the original film, the four planned sequels have "fully encapsulated" standalone plots that "come to their own conclusions". All four films have an overarching meta-narrative that connects them and have the Sully family at the center. James Cameron described the sequels as "a natural extension of all the themes, and the characters, and the spiritual undercurrents" of the first film.