The Toronto District School Board voted overwhelmingly to implement a ban on cellphone use on school property during school hours.
The vote, which happened late Wednesday night, has the support of many trustees and teachers who believe the devices are disruptive, distracting and are easily being used by students to cheat.
The board will send a mass communication to principals across the system informing them of the new rules.
Ahead of the vote, trustee Josh Matlow said students have been using cellphones to snap pictures or shoot videos of tests. Such cases have been reported at several U.S. schools.
"Text messaging and emailing back and forth is the modern way of passing notes," Matlow said. "And that's what's happening every day in our schools and we want to do something about it."
While many schools have individual policies about cellphones in the classroom, there had been no board-wide ban established in Toronto.
Matlow's proposal received support from school officials, including North Toronto Collegiate Institute principal Joel Gorenkoff.
"I think it's overdue," said Gorenkoff, who adds North Toronto has already instituted its own ban.
The ban still allows students to bring cellphones to school, but they would have to leave school property to use them.
The Dufferin-Peel Catholic District School Board became the first local board to ban the devices when it did so in February.
That rule also prohibits the use of other handheld electronic devices, such as BlackBerrys and iPods, from after-school sports and during field trips.
With reports from CTV's Galit Solomon and Chris Eby