The dean of a Brooklyn middle school was stabbed Monday afternoon while defending a young student from a group of teens who jumped him, police said.

The 29-year-old administrator at IS 383 Philippa Schuyler was cut to the arm while trying to break up the skirmish between a 13-year-old student and the teen aggressors outside the Bushwick school around 4 p.m., cops said.

The dean was taken to Brookdale Hospital in stable condition.

The 13-year-old student was not injured.

The teens who reportedly jumped the 13-year-old were not students at the school, police and sources said. They fled in an unknown direction and remain at large.

The investigation is ongoing.