Three teenage boys were stabbed on an MTA bus after school let out Thursday afternoon, police said.

A “large fight” broke out aboard the M96 as it traversed East 96th Street at Third Avenue on the Upper East Side just after 3:30 p.m., police said.

An unknown suspect pulled out a knife and stabbed or slashed two 15-year-olds and a 16-year-old during the brawl, according to cops.

The older victim was cut on his left elbow and the two younger teens suffered injuries to their right shoulder and left leg respectively, the NYPD said.

All three boys were taken to Manhattan hospitals in stable condition, authorities said.

It was unclear if the victims were students. There are about a dozen high schools in a ten block radius of the attack, according to maps of the area.