According to Hemet police, students at West Valley High School began fighting each other at approximately 1:15 p.m.
Video shows dozens of students involved in the altercation as additional officers were called to the scene.
The school resource officer ended up on the ground with a student after attempting to stop the student from assaulting another student, police said.
The school resource officer was kicked and punched in the back by another student.
Five students -- four juveniles and one adult -- were arrested.
The students arrested face several charges, including assaulting school staff, assaulting a police officer, resisting arrest, and resisting arrest by threat or violence.
No one was seriously hurt in the altercation.