Three separate fights caused Lincoln High School to be locked down for 45 minutes today.
City police arrested seven students, said Fernando Gallard, a spokesman for the Philadelphia School District.
The lockdown started at 1:15 and was lifted at about 2 p.m., Gallard said.
"At this point, the school is looking into what started the fights," he said.
Lincoln, on Ryan Avenue in the Northeast, has about 1,800 students.