A 16-year-old boy was busted at a Queens high school while flashing a firearm to impress his friend, police sources said Friday.

The teen, who has no prior run-ins with the law, was arrested at Epic High School in South Richmond Hill on Thursday afternoon with a Glock-26 in his backpack, the sources said.

School safety agents were alerted to the gun after another student spotted the teen showing off the piece and reported it, sources said.

The boy was handed off to cops and was booked on gun charges.

Sources said he refused to tell cops where he got the firearm.