She doesn’t just deserve a lump of coal in her stocking, she should get a whole trainload!

A bah-humbug New Jersey substitute teacher shattered the hearts of a class of first-graders by telling them Santa Claus and his eight reindeer weren’t real — and then it got a lot worse.

“She proceeded to just completely unleash on them,’’ said stunned parent Lisa Simek, whose daughter Emilia was in the class at Cedar Hill School in Montville, on Facebook.

“She told them Santa isn’t real and parents just buy presents and put them under their tree.

“She told them reindeer can’t fly and elves are not real — [and] elf on the shelf is just a pretend doll that your parents move around. She did not even stop there: the tooth fairy is not real

because mom or dad just sneak into your room in the middle of the night and put money under your pillow, same goes for the Easter bunny.

“She told them magic does not exist. There is no such thing as magic anything,’’ Simek wrote. “A grown woman tried to crush our 6-year-old’s spirit, along with the spirits of the other 22 kids.”

One parent said the substitute teacher’s rant even targeted leprechauns.

Some of the children refused to believe the Scroogey sub, known as “Ms. M,’’ when she announced the Christmas spirit-stomping news Thursday.

“The children began yelling that everything is real,” one parent, Mayra Aboyoun, wrote on Facebook. “My daughter is completely heartbroken!”

Another woman told The Post that her 6-year-old granddaughter was beside herself.

“My granddaughter came home yesterday and told me, ‘Mimi, Santa Claus isn’t real.’ And I flipped out,” the woman recalled.

“I had to explain to her, ‘Santa is real, if you believe, Santa is real. Don’t listen to other kids blah, blah, blah. I thought the kids had did it. I didn’t realize it was a substitute teacher.”

The sub launched into her Grinch-like diatribe during a writing activity, said the school district’s superintendent, Rene Rovtar.

“A student had written that Santa was real, and the substitute teacher decided to dispel that,” Rovtar told The Post. “Some of the students were very upset.”

The sub’s coldhearted behavior came to light because another adult who was in the room at the time reported it to the school’s principal, Michael Raj, according to district officials.

Raj, rightly predicting an outcry over the sub’s Christmas jeer, swiftly drafted a letter to parents that evening.

He told the parents that he was giving them a heads-up in case their kids had questions about whether St. Nick was legit.

“[I’m writing] so that you are aware of the situation and if the conversation comes up at home over the next few days you can take appropriate steps to maintain the childhood innocence of the holiday season,” he said in the letter, a copy of which was obtained by The Post.

“During the course of the day, a substitute teacher apparently announced to the class that Santa was not real. As a father of four myself, I am truly aware of the sensitive nature of this announcement.”

Raj said he gave the substitute teacher a talking-to about her “poor judgment in making this proclamation.”

Rovtar declined to say whether the sub, who has taught at the school for at least two years, would be allowed to teach in the future.

Some parents are livid at the prospect that she could be back in the classroom.

“Parents are infuriated,” said Tammy Stappas, vice president of the school’s Home and School Executive Board. “They don’t want this woman teaching at the school anymore.”

Rovtar called the sub’s behavior “very disheartening.

“It’s distressing to us,’’ she said. “The childhood wonder associated with all holidays and traditions is something I personally hold near and dear in my own heart.”