Platt High School in Meriden was placed on lockdown Monday after fights broke out in the cafeteria during lunch.
Police were called to the scene after the school resource officer could not get the fight under control, according to Sgt. Darrin McKay.
In a message to parents, Interim Principal David Levenduski said two separate altercations occurred and the school was placed on lockdown to ensure the safety of the large number of students in the cafeteria at the time of the incidents. There were no major injuries, he said.
There were fewer than 10 students involved in the fights, according to Superintendent Mark Benigni.
"I applaud the staff, our school administrators, and our police department for their swift action to assure that we maintained safety in one of our school's most highly populated areas," Benigni said in a statement.
Five students were arrested, according to McKay. Those arrested were believed to be the instigators of the fights, he said.
Police remained at the school for the rest of the day.