A Bronx principal ordered her teachers to give up their desks last week, and had the furniture dumped at the curb — telling staff she doesn’t want them sitting in class.

Donna Connelly, principal of PS 24, the Spuyten Duyvil School in Riverdale, also told teachers to empty their filing cabinets, which she then discarded. With class in session, teachers were told to push their desks and cabinets into the hallway. Custodians then hauled them outside and piled them like trash on the blacktop of a school across the street.

“It’s the 21st century — you don’t need desks,” Connelly said, sources told The Post.

The diktat demoralized staff at the K-5 school, where diverse students perform well above the city average on state exams.

Connelly told teachers she “does not want them sitting,” an insider said, although no chairs were tossed.

“Figure it out,” she snapped when staffers asked where to store their supplies, a source said.

As to where teachers should grade papers, Connelly answered, “Use the lunch room,” sources said.

Teachers had to remove student paperwork and items such as devices to help kids with asthma.

“All their stuff is in boxes, bags and on the radiators,” a source said.

Children watched as the furniture was cleared out, one said. “The kids saw their teachers upset about what was going on. It was dehumanizing.”

Photos of the desk dump made it onto a teacher’s Facebook page, sparking dozens of outraged comments.

“Thirty years in the system and I’ve never seen anything like this,” a Bronx teacher commented.

“How the f–k does someone with so little good sense become a principal? What kind of policy allows this to happen?” another posted.

“She is nuts!” wrote another.

Word spread to District 10 Superintendent Melodie Mashel, who on Friday ordered the furniture returned to PS 24 — and out of public view. But it was stacked in the basement, sources said.

Connelly did not return messages. A city Department of Education spokesman said the furniture was moved “to ​facilitate better instruction.”​