"Ontario's students need to be able to focus on their learning - not their cellphones", she wrote.
It will be up to individual schools and boards to enforce the ban, and exceptions would be made when teachers want to use cellphones as part of their lesson, for medical reasons and students with special needs.
Although some Ontario schools have similar policies in place already, the ban would require all public schools to introduce the ban in the upcoming school year.
In 2017, a Toronto middle school implemented a ban on the use of cellphones in classrooms.
"I think it's a good idea", says Lynn Hutchinson, a local teacher in Windsor.
While Green Party Leader Mike Schreiner agrees that cellphones can be a distraction, he is critical of what he describes as the government's "top-down regulation" approach.
He said there was a ban at his school, Prince Andrew High in Dartmouth, around a decade ago.
"Teachers see the value of technology as an enhancement to learning and they are using it pretty powerfully, but we also see teachers and principals making judgments where to pull back", he said. "Students have learned about ensuring positive digital citizenship and creating personal digital footprints".
Education consultation surveys from a year ago suggested that approximately 97 percent of respondents supported some form of restriction on phones in class, according to the government sources. About 97 per cent of respondents favoured some sort of restriction on phones in class.
One of these government sources explained to CTV News, "When the school day starts, the phones go off".
The Conservatives had proposed the ban during last year's election campaign.
Nova Scotia's education minister says the province won't ban cellphones in 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. "I think the teacher should be in control of the technology and so the teacher should be bringing the technology to the classroom".
Instead, McRae said schools should be helping students find a healthy balance for their cellphone use.
In 2015, NY ended its ban on cellphones, giving schools the authority to create their own, in part because parents wanted to be able to contact their children, and it was not equally enforceable.