Ishu Gupta was reportedly engaged in a confrontation with his batchmate Krishna during extra classes in the school.
Krishna along with three-four people allegedly stabbed Ishu outside Rajkiya Sarvodaya Bal Vidyalaya No 2 in Shakarpur area of Delhi.
The victim was rushed to a hospital where he was declared dead.
Police have detained seven people including five minors.
The motive behind the attack is under probe.