Lansdowne police said at least eight students could be charged in connection with the altercations.
William Penn School District officials said the investigation into what sparked each melee is ongoing.
"Once that investigation is concluded we will take the necessary actions," said Superintendent Dr. Eric Becoates.
Officials also said at least five different fights unfolded.
Police said they are aware of three.
Leaders initially called for students to shelter in place and, after meeting with police, decided to dismiss students early.
"We did ensure that students exited the building safely and we did allow families to come back with their students up to 3:30 to get their belongings that may been in a locker," Becoates said.
NEW: @6abc obtained videos of two fights that occurred today at Penn Wood High School in Delaware County.— George Solis (@GeorgeSolis) October 26, 2021
School officials said there may have been at least five that led leaders to dismiss students early.
Criminal charges may also be filed.@6abc pic.twitter.com/3UCus7hEq6
The videos shows some students fighting among themselves and also with school staff.
"Wow, are they fighting the security guards?" noted one parent who witnessed the videos.
Daelicia Reeves, who got the call to pick her children, was in disbelief over the violence.
"It's disturbing. It really is," Reeves said.
School officials said they've yet to decide if classes will resume on Wednesday.
No serious injures were reported as a result of the fights.