Randallstown High School was placed on a brief lockdown after there were reports of a student with a gun.
According to Baltimore County Police, there was a fight between students and administrators were told that someone had a gun.
The school identified four students that appeared to be passing around a gun, but they later found out it was a BB gun, according to police.
All four students were arrested and have charges potentially pending.
Baltimore County Schools said the school is no longer on lockdown.