The earthbender rebellions were a series of armed uprisings against the Fire Nation occupation of the Earth Kingdom, formed during the later stages of the Hundred Year War. However, despite the conflict's name, the very mass of the rebels were non-benders who were led by earthbenders. The first known rebellions in occupied territory occurred in winter 99 ASC, but they became widespread some time after the Coup of Ba Sing Se in 100 ASC. Their success alarmed the Fire Nation, as GeneralShinu admitted that the powerful Fire Nation armies in the Earth Kingdom had been unsuccessful in repressing the revolts and that domestic forces would be required for reinforcement.
The first towns to be liberated from the Fire Nation's suppression were smaller villages and towns at the western Earth Kingdom coast; after Team Avatar freed many earthbenders from a prison rig, they vowed to reclaim all their villages, thus starting the rebellion in the smaller cities. Although many of these earthbenders were civilians and had no combat experience, they formed any effective militia and later on they even came into possession of combat equipment.
After the Capture of Omashu, and in course of the following Fire Nation occupation, a resistance movement was formed by Captain Yung of the Earth Kingdom Army. The resistance members were determined to use every means to liberate the city, including assassinations and kidnappings. However, as their actions proved to be futile, the resistance eventually evacuated all members and sympathizers in the hopes of fighting another day.
On the Day of Black Sun, KingBumi successfully broke free of his metal prison and, taking advantage of the soldiers' inability to firebend, used his exemplary earthbending abilities to defeat all of the powerless guards and soldiers who were trying to stop him. With the guards defenseless, Bumi began to take back his city.
Bumi cast out every Fire Nation-constructed building, and he destroyed the statue of Fire Lord Ozai to signify Omashu's liberation. With some effort, he elevated the earth underneath the statue, causing it to crash directly into the governor's house and destroy the metal bridge over the abyss.
The liberation of Omashu was a disaster for the Fire Nation, as it lost one of its major strongholds in the western Earth Kingdom.
After Azula successfully overthrew the Earth Kingdom government by conquering the capital city, Ba Sing Se, during the Coup of Ba Sing Se, Fire Nation forces were sent in all remaining free territories of the continent. However, many rebellions occurred as an attempt to regain control of the Earth Kingdom. These oppositions proved to be such a challenge for the sparse Fire Nation soldiers that the rebellions were brought to the attention of Fire Lord Ozai. Building on Zuko's field experience, Ozai realized that the rebellions were able to be sustained due to the hope that the Earth Kingdom citizens possessed, so he planned to destroy their hope by burning down the Earth Kingdom during Sozin's Comet. When Sozin's Comet arrived, Aang defeated the Fire Lord, and Ba Sing Se was liberated from the Fire Nation by the members of the Order of the White Lotus, which finally ended the Hundred Year War.