A Brooklyn public school teacher was slashed across the chest by a student while trying to break up a fight on Wednesday, according to police and law enforcement sources.

The incident unfolded around 2:45 p.m. at the Knowledge and Power Preparatory Academy, a middle school in Brownsville, the NYPD said.

The teacher intervened after witnessing the feuding teenagers and was struck with a knife.

The educator received minor injuries and was treated by EMS at the school.

The knife-wielding 16-year-old boy was taken into custody and a weapon was recovered.

The Department of Education did not immediately respond to The Post’s request for comment.

The attack came just hours after two teen boys were slashed outside their Queens public high school.

The victims, 15 and 16, were knifed on their arms around 9:45 a.m. by an unknown assailant inside a park right next to Newcomers High School in Dutch Kills, police said.