The Pakistan military said another militant has been sentenced to life in prison.
The seven have been found guilty of being linked to the deadly school attack -- but did not participate in the attack in which all the gunmen were killed.
The Pakistan army statement Thursday said the militants had been tried in Pakistani military courts and have the right to file an appeal before the country's court of appeals.
The Taliban attack on the Army Public School and Degree College in Peshawar killed 145 people -- including 132 children, 10 staff and three soldiers.
More than 100 others were injured in the siege that deliberately targeted the school's 1,100 students, most of whom were the children of army personnel.
Pakistan lifted a seven year moratorium on the death penalty
a day after the massacre and amended its constitution to allow military courts to try those accused of terror attacks.
In response to a series of deadly attacks, Pakistan carried out its first executions for terrorism just days after the Peshawar school massacre -- the first civilian hangings since 2008.
Despite this measure, deadly attacks continued.
In February this year, the Taliban claimed a suicide bombing on a Shiite Mosque in Peshawar that killed 19 and injured 67 people was a revenge attack for the execution of Mohammed Aqeel, who was condemned for his role in a 2009 attack on an army headquarters in 2009.
One month later, suicide bombers targeted a Christian community near Lahore, killing 14 people and wounding another 78.
Pakistan's Taliban claimed responsibility for that attack and declared such events would continue until Sharia Law was implemented in Pakistan.
The March, 2015 bombing
occurred just days after the Taliban's three major splinter groups announced they were uniting as the Tehrik-i-Taliban or TTP.
As recently as May 2015, Jundullah, a Taliban splinter group, attacked a bus carrying Muslim pilgrims in Karachi, killing 45 people.