The incident took place in Orange County on Monday, March 6 at Middletown High School.
The fight took place in a hallway outside a classroom.
The teacher was injured while attempting to intervene, said Amy Creeden, Superintendent of Schools for the Enlarged City School District of Middletown.
"This saddens our entire school community and we are thinking of the faculty member during this difficult time," Creeden said in a letter to staff.
Security staff responded immediately, arriving at the altercation less than two seconds after it began. Within 30 seconds after the fight began there was nine security staff on the scene, Creeden said.
"The matter is currently under investigation and being handled with the utmost seriousness," she added.
Creeden said the type of misconduct that happened on Monday would not be tolerated.
Middletown Police had not responded regarding any charges or arrests as of Thursday, March 9.
This is a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice Mamaroneck and receive free news updates.