A 27-year-old teacher was arrested after he allegedly put a 15-year-old student in a headlock at a Brooklyn high school, according to police and sources.

The shocking incident at the High School for Sports Management took place Tuesday around 12:30 p.m., sending the injured student to Maimonides Midwood Community Hospital in Brooklyn, police and the sources said.

The teacher, Gary Zeng, allegedly attacked the youngster after he entered his classroom without permission, according to sources.

“This alleged behavior is completely unacceptable, and nothing is more important than the safety and well-being of our students,” a spokesperson for the city Department of Education said in a statement. 

“This employee has been reassigned away from students pending the outcome of the arrest, and if convicted, we will pursue termination.”

The deranged teacher was taken into custody and charged with second-degree strangulation, criminal obstruction of breathing, endangering the welfare of a child, and third-degree assault, police said.

It is not immediately known what sparked the alleged assault.

The victim, who sustained injuries to his neck, remains in stable condition, police said.