Avatar: The Last Airbender season 3

Book Three: Fire brings the animated series Avatar: The Last Airbender to a close. In this final season, Aang must master Firebending while his friends Katara, Sokka, and Toph work to stop the tyrannical Fire Lord Ozai before Sozin's Comet arrives. Meanwhile, Prince Zuko is finally accepted back into the Fire Nation after turning against his uncle Iroh and helping his sister Azula capture Ba Sing Se in the previous season.

The season aired on Nickelodeon from September 21, 2007, to July 19, 2008, with 21 episodes ending in the four-part finale "Sozin's Comet." It was produced by Nickelodeon Animation Studio, with co-creators Michael Dante DiMartino and Bryan Konietzko serving as executive producers alongside head writer Aaron Ehasz. Directors included Ethan Spaulding, Lauren MacMullan, and Giancarlo Volpe, while the writing team consisted of Ehasz, Elizabeth Welch, Tim Hedrick, John O'Bryan, DiMartino, and Konietzko. Music was composed by Jeremy Zuckerman and Benjamin Wynn, known as "The Track Team."

The main voice cast remained consistent: Zach Tyler Eisen as Aang, Mae Whitman as Katara, Jack DeSena as Sokka, Michaela Jill Murphy as Toph, Dante Basco as Zuko, Dee Bradley Baker as Appa and Momo, and Grey DeLisle as Azula. Mark Hamill returned as Fire Lord Ozai in a larger role after minor appearances in earlier seasons, and Greg Baldwin took over the role of Iroh following the death of Mako Iwamatsu in July 2006.

Critics praised the season, and it won a 2008 Peabody Award. Reviewers highlighted the solid writing, colorful animation rooted in Asian folklore, and smooth execution. The series finale received glowing reviews from outlets like The New York Times and Toon Zone. The season also earned praise for its video quality and sound. At the 2008 Annie Awards, it won Best Animated Television Production for Children, and Joaquim Dos Santos won Best Directing for "Into the Inferno." Dos Santos also earned a nomination at Annecy 2008 for "The Day of Black Sun Part 2: The Eclipse." Music editor Jeremy Zuckerman and the sound editing team were nominated for a Golden Reel Award for Best Sound Editing in a Television Animation for "Avatar Aang."

Paramount Home Entertainment released four DVD volumes between October 30, 2007, and September 16, 2008, with a complete box set following.