A New Jersey preschool teacher allegedly threatened colleagues that she would shoot up the school, authorities and reports said Wednesday.

“One day, I’m gonna come here and shoot it up,” Gina Schroeder allegedly told fellow teachers at The Goddard School in Elmwood Park on Friday, prompting them to call the cops.

Police briefly placed the school on lockdown and detained Schroeder, who had no weapons on her.

Investigators also searched Schroeder’s Nutley home, where they seized three guns the teacher legally owned, NJ.com reported, citing Elmwood Park cops.

Schroeder was charged with making terroristic threats and illegal possession of prescription drugs.

In a biography since pulled from the school’s website, Schroeder was listed as the lead teacher in the infant classroom, according to NJ.com.

With Post wires