A 14-year-old boy was busted for bringing a loaded gun into his New York City school on Wednesday — making him the third teen caught with a weapon in Big Apple classrooms this week, according to police.

The teen was cuffed after a fight with another student led authorities to finding the .380 semi-automatic weapon stashed inside his backpack at the School of Earth Exploration and Discovery – Harlem, also known as SEED Harlem, on West 130th Street around 1 p.m., the NYPD said.

Police said the gun’s magazine was loaded, but the chamber was empty.

The teen was cuffed after a fight with another student led authorities to finding the .380 semi-automatic weapon stashed inside his backpack at the School of Earth Exploration and Discovery – Harlem. Google maps

No serious injuries were reported in the scuffle between the two middle school students.

Charges against the teen are still pending, police added.

The incident comes after two other students were found armed in city schools Monday morning.

A 17-year-old male, who sources said was already wanted in connection with a Bronx shooting, was found with a firearm inside the Harlem Renaissance High School just after 10 a.m., according to police.

Charges against the teen are still pending, police said. Gregory P. Mango

The incident comes after two other students were found armed in Big Apple schools Monday morning. Google maps

He was charged with criminal possession of a firearm.

That same day, police stormed Long Island City High School in Queens and nabbed a 15-year-old student who had a gun hidden in his backpack, cops said.

Sources told The Post that an eagle-eyed staff member noticed that the teen was armed and notified the school safety agent, who in turn reported it to police.

The boy was charged with two counts of criminal possession of a weapon.

Wednesday’s incident remains under investigation.