Sei Iori is a Gunpla builder whose family runs a hobby shop in a small town. He aspires to be a Gunpla Battle champion like his father, but despite his exceptional building skills, he lacks the combat abilities to compete with other contestants. Then one day, he meets a mysterious boy named Reiji, who helps him improve his confidence in participating in Gunpla Battles. Together, Sei and Reiji battle their way to the 7th Gunpla Battle World Tournament.

Gundam Build Fighters ran for 2 seasons. No new episodes are scheduled.