A Manhattan teacher claims that she was let go from a city school because she tried to blow the whistle on guns being brought in by students, according to a new lawsuit.

Angela King says that on Nov. 30, 2017 a student at the High School for Fashion Industries in Chelsea showed her a Snapchat video of kids “in the school waving guns in the air,” her Manhattan Supreme Court lawsuit says.

King alerted other school officials who later that day deleted the video off of the student’s phone, the suit, filed Thursday, says. Then over the loudspeaker the principal said, “gun(s) were found in the building, but don’t worry because the gun(s) were fake, I repeat, the guns were fake,” the court papers said.

King’s students laughed at the announcement and some said, “this school really doesn’t care about the students, and they think we are stupid, they only care about ratings so that they can look good and lie to our parents about the school and the safety at this school, only because they want to be on the safe school list,” the court documents charge.

They told King the kids in the video were the same ones who had been stealing hallway passes, the court papers say.

The kids who brought the guns to school then posted on Snapchat “that they were released after being arrested and said they would be back at school the following day,” the court papers say other students informed King.

One of the kids, months later, came to her classroom and threateningly called her a “snitch,” the court documents say.

NYPD spokesperson Sophia Mason said juvenile police reports were filed against two people over the incident. Mason called the guns “imitation firearms.”

In February 2018 King — who started at the school four years prior — got a negative review despite months earlier receiving assurances she was a shoe-in for tenure. Then, toward the end of that school year in May 2018, she was informed they wouldn’t be renewing her contract, the court papers say.

“As a result of Plaintiff’s proactive efforts once alerted to a potentially deadly situation within the School, student safety was ensured, and potentially senseless tragedy was averted,” the lawsuit claimed. “However, instead of praising Plaintiff for her role in thwarting any violence on November 30, 2017, Defendants have instead subjected Plaintiff to unwarranted harassment and retaliation.”

“The School is attempting to push Plaintiff out the door in response to her having inside information about how the gun incident … actually unfolded,” the court papers allege.

King’s lawyer, Jonathan Tand, told The Post, “it’s an outrage what they did to her. She was trying to protect the students and they retaliated against her.”

King sued the Department of Education and three top school officials for unspecified damages.

A rep with the DOE, Danielle Filson, said “We’ll review the suit when we receive it.”

The city Law Department deferred comment to the DOE.

Additional reporting by Selim Algar