The Canadian Press has learned that Ontario is set to announce this week that cellphones will be banned in classrooms, starting in the next school year.
Some schools already have similar policies, but the province will issue a directive to all public schools for the 2019-20 school year.
It would prohibit cellphone use during instructional time.
Enforcement of the ban would be up to individual boards and schools.
The Progressive Conservatives had proposed such a ban in their platform during last year's election campaign.
Government sources who were not authorized to speak publicly ahead of the announcement say exceptions would be made for when teachers want to use cellphones as part of their lesson, for medical reasons and students with special needs.
"When the school day starts, the phones go off," one senior government source said. "It's about recognizing that a school is a learning environment."
The Tory government conducted education consultations last year, and while input on the sex-education curriculum dominated headlines, feedback was also gathered on a potential classroom cellphone ban.
About 97 per cent of respondents favoured some sort of restriction on phones in class, the sources said.
"It was the closest thing we got in our consultation to unanimity," one source said.
The Toronto District School Board used to have a cellphone ban, but reversed it after four years to let teachers dictate what works best for their classrooms. The board has previously said that enforcing an outright ban was next to impossible, and said that to curb technology use would be to place limits on educational opportunities as well.
A 2015 London School of Economics and Political Science paper found that "student performance in high stakes exams significantly increases" with a ban on mobile phones. The improvements were largely seen among the students who were normally the lowest achieving.
"This suggests that restricting mobile phone use can be a low-cost policy to reduce educational inequalities," the study found.