The collapse, in Peshawar, also killed a teacher and injured more than 40 people. The country's prime minister urged rescuers to speed up the search for survivors.
Asim Khan from Peshawar's Lady Reading Hospital confirmed the toll to AFP, adding that more than 30 people were injured, with six believed to be in a critical condition.
The roof of a private school collapsed in northwestern Pakistan on Thursday, killing at least 10 children and injuring more than two dozen others, an emergency services official said.