Under a new law signed by the state’s Democratic governor, Gavin Newsom, on Monday, school districts in California must enact rules limiting their students’ smartphone use.

The law requires school districts to adopt rules restricting or prohibiting student use of smartphones on campus or while under the supervision of school personnel by July 1, 2026. After that, school districts must update their policies every five years.

With this law, California becomes the latest state to attempt to restrict students’ cell phone access in an effort to minimize classroom distractions and counteract the effects of social media on children’s mental health.

“This new law will help students focus on their studies, their social development and the world in front of them while in school, not on their screens,” Newsom said in a statement.

Florida, Louisiana, Indiana and several other states have passed laws to restrict students’ cellphone use in school. New York Governor Kathy Hochul said in May she would support a ban on smartphones in the state’s schools. The Los Angeles school district, the second-largest in the U.S., voted to ban students from using cellphones during the school day starting in January.

Critics of cell phone bans say teachers should not be responsible for enforcing them. Others worry that the rules will make it harder for students to seek help in an emergency or argue that decisions about cell phone bans should be left to individual districts or schools.

“We support those districts that have already acted independently to implement restrictions,” said Troy Flint, a spokesman for the California School Boards Association. “We are simply against the mandate.”

The move comes after Newsom signed a law in 2019 authorizing school districts to restrict students’ cellphone access. In June, he announced plans to revisit the issue after the U.S. surgeon general urged Congress to mandate warning labels on social media platforms about their impact on young people. The governor then sent letters to districts last month urging them to limit student device use on campus.

Josh Hoover, a Republican from California who represents Folsom, introduced the bill to a bipartisan group of lawmakers who are also parents.

At the school where Hoover’s children — ages 15, 12 and 10 — are allowed to use cell phones, a rule many students don’t like, which in part shows how addictive cell phones can be, he says.

“I think overall they understand why it’s important, why it helps them focus better in class and why it actually helps them interact better with their peers face-to-face in school,” he said.

Before student cellphone use was banned during the school day at Sutter Middle School in Folsom, students were seen recording fights, filming TikTok challenges and spending their lunch periods watching online content, said Principal Tarik McFall. The rule has “completely changed the culture” of the school, causing students to spend more time talking to each other, he said.

“Putting them away, turning them off and practicing that was a great thing,” McFall said.

Teachers have reported increased student participation since the Santa Barbara School District implemented a complete ban on cellphone use in class for students in the 2023-24 school year, said Assistant Principal ShaKenya Edison.

Some parents have expressed concerns that banning cellphones at school could cut them off from their children in the event of an emergency. Those fears were heightened after a shooting at a Georgia high school this month left four people dead and nine injured.

The 2019 law that authorizes districts to restrict students’ cellphone access includes exceptions for emergencies, and the new law does not change that. Some supporters of cellphone restrictions in schools say it’s better to turn off cellphones in a school shooting situation so they don’t ring and give away a student’s location.