A statement on the Pakistan military's website said seven militants were found guilty of links to the attack - only one had been given a life sentence instead of the death penalty.
Photo released by the Pakistani Taliban showing the men who stormed the military-run school in Peshawar
The men who shot the children all died in the assault
"The convicts were given fair trial by following all the legal formalities and offering/providing them legal aid and defence counsels," the statement said.
"Today the sentences of death have been confirmed by the Chief of Army Staff."
These are the first death sentences to be handed out in connection to the Army Public School massacre, the BBC's Shaimaa Khalil reports from Islamabad.
Those facing the death penalty are not the seven who took part in the attack - all of whom died in the assault.
They scaled the walls to get into the school and set off a bomb before moving from classroom to classroom shooting indiscriminately at both the children and teachers.
The school was near a military complex in Peshawar and many of its students were the children of military personnel.
Peshawar, which is close to the Afghan border, had seen some of the worst of the violence during the Taliban insurgency in recent