The brawl began around 1:30 p.m. Thursday and officials quickly locked the school down.
Police arrested 11 students and charged them with fighting on campus; some will also face charges of assaulting campus security.
Investigators say it is still unclear exactly how the fight began, but ABC7 media partner The Contra Costa Times reports that it started when a black student approached a Hispanic student and told him his gang was no longer welcome on campus.