According to the Fresno Fire department, it happened at Yosemite Middle School Sunday night.
Fire officials say the three took materials from the school, gathered them into a pile in front of a door and lit it on fire.
Damage to the school was minimal, but fire investigators will review surveillance video for their investigation.
Fresno Police detained the three juveniles.
We've reached out to Fresno Unified School District for more information but have not heard back.
Stay with ABC30 for the latest details on this developing story.