77 students were hospitalised in two separate attacks in the north of the country.
Mohammad Rahmani, the director of the provincial department of education, said the attacks took place among female pupils in grades 1 through 6 in the Sar-e-Pul province over Saturday and Sunday.
60 students from Naswan-e-Kabod Aab School and 17 from Naswan-e-Faizabad School were poisoned.
“Both primary schools are near to each other and were targeted one after the other,” he said on Sunday.
“We shifted the students to the hospital and now they are all fine.”
Since the Taliban swept to power in August 2021, there has been a crackdown on the rights and freedoms of Afghan females.
Girls in the country are banned from education beyond sixth grade, including university, and women are barred from most jobs and public spaces.
Mr Rahmani said that early investigations showed that someone with a grudge paid a third party to carry out the attacks.
The education official did not give details on how the girls were poisoned, or the nature of their injuries.
Neighbouring Iran has been rocked by a wave of poisonings, mostly in girls' schools, dating back to last November.
Thousands of students said they were sickened by noxious fumes in the incidents, but there has been no indication of what might be behind the incidents or what if any, chemicals have been used.