The fourth season of Star Wars: The Clone Wars, subtitled Battle Lines, consists of twenty-two episodes. It debuted with "Water War" and "Gungan Attack" on September 16, 2011 on Cartoon Network, and concluded with "Revenge" on March 16, 2012.
The battle to save the galaxy reaches new heights of peril and new depths of darkness. The valiant Jedi Knights and clone troopers defend exotic planets from enemy forces. They wage war underwater, battle across a night-shrouded world and take on the merciless Death Watch. Our heroes are tested like never before as Anakin is haunted by the realities of his past, Ahsoka fights to free her people, and an undercover Obi-Wan braves a deadly bounty hunter tournament. Season Four culminates with the shocking return of a villain from the past: the ruthless Darth Maul, who will stop at nothing to achieve vengeance.
- Matt Lanter as Anakin Skywalker
- Ashley Eckstein as Ahsoka Tano
- James Arnold Taylor as Obi-Wan Kenobi
On July 2, 2012, Star Wars.com announced Season 4 would be released on Blu-Ray and DVD on October 23, 2012. In addition to this, the behind-the-scenes special features of the release were announced as well, including the five special episode commentaries, special effects footage and extended/deleted scenes.
- Star Wars: Clone Wars Adventures released a campaign mini-game titled "Mission on Iceberg Three" on July 15th as an introduction to the Battle of Mon Calamari. Players were tasked with battling General Grievous and his forces on Iceberg III to stop Separatist advances in the Calamari system.
- This was the first season to not have a trailer for the next season right after the finale.