MISSISSAUGA, Ontario — The troubles began over sermons.
For nearly two decades, Muslim students in the Peel School District, outside Toronto, had been allowed to pray independently on Fridays, part of a policy in many Canadian provinces to accommodate religious beliefs in public schools.
Last fall, the school board decided to standardize the prayer sessions and offer six preapproved sermons that the children could recite, rather than let them use their own.
But the dispute unleashed a storm of protest that continued through this spring.
Demonstrators are picketing school board meetings, arguments are eruptingon social media about whether religious accommodation is tantamount to special treatment, and there is a petition drive to abolish prayer in the public schools. In April, a local imam who supported the board received a death threat. The local police now guard the school board’s meetings.
The turmoil is one reflection of how Canada’s growing diversity is encountering powerful headwinds, especially in places with significant Muslim populations.
“Although we have a policy of multiculturalism, for most Canadians there is an expectation that immigrants will conform to the mainstream,” said Jeffrey Reitz, the director of the Ethnic, Immigration and Pluralism Studies program at the University of Toronto. “Religious accommodations have been made to various groups, and you’re going to get a backlash once in a while.”
The problems in the Peel schools are a particular kind of conflict in a diverse society, social scientists say — involving immigrants and minorities who challenge aspects of Canada’s cherished multiculturalism.
In 2015, socially conservative residents in Ontario school districts, some of them Muslim, objected to an updated sex education curriculum because it teaches the names of sex organs and broaches the topic of same-sex relationships.
Since 2013, some Muslim parents in metropolitan Toronto have asked schools to exempt their children from mandatory provincial music classes, citing their belief that Islam forbids listening to or playing musical instruments.
Like its neighbor to the south, Canada is a country of immigrants, helping to fuel a national ethos that celebrates diversity. More than 20 percent of the Canadian population in 2011 was foreign born, a figure that is expected to reach nearly 30 percent by 2031, according to government estimates. In cities like Toronto and Vancouver, the proportion of ethnic minorities could top 60 percent.
The demographic changes have been especially pronounced in metropolitan Toronto, a patchwork of cities and suburban towns bustling with an array of languages and faiths.
School boards like the one in the Peel district are at the forefront of the battles over multiculturalism. The district is among the country’s most diverse, with nearly 60 percent of all residents described as “visible minority,” or nonwhite, according to the 2011 census.
It includes large numbers of Chinese, Filipinos and blacks, but nearly half are categorized as South Asian, a group that includes Sikhs, Hindus and Muslims. The Peel district is home to about 12 percent of Canada’s Muslim population.
In allowing prayer in its schools, the Peel district relied on a provision in the Ontario Human Rights Code that the Ontario Human Rights Commission has interpreted as requiring government-funded schools — both public and Catholic — to “accommodate” students in observing their personal faiths.
Other provinces in Canada have similar policies.
For Farina Siddiqui, 43, a Muslim activist whose children attend public and Catholic schools in the Peel district, allowing students to worship once a week in school is a matter of religious freedom.
“We’re not asking for schools to provide a prayer hall for everyone to practice a religion,” she said. “We just ask for the right to have a space to pray.” She supported permitting the children to write their own sermons.
Tarun Arora, 40, who works for an outsourcing call center company and immigrated to Canada from India in 2003, said school boards should not be endorsing sermons or allowing prayer in his children’s public schools at all. He wants the schools to be completely secular.
“I’m sending my kids to school for education, but the schools are being treated as religious places, and this is not right,” Mr. Arora said.
He is a member of Keep Religion Out of Our Public Schools, also known as Kroops, a group that formed in January when the board decided to allow the children to write their own sermons. The group has protested outside recent school board meetings and says it plans to bring a lawsuit challenging the policy of allowing prayer in the Peel schools, arguing that the law does not explicitly permit it.
Another group with a similar name, Religion Out of Public Schools, began an online petition to eliminate religious congregation and faith clubs in Canadian schools. It has garnered over 6,500 signatures from people across Canada and the United States.
Many of the petition comments specifically criticize Islam. But in interviews, three members of the group, all of them Indian-Canadian, said they opposed the practice of any religion in public schools, not just Islam.
Renu Mandhane, the chief commissioner of the Human Rights Commission, which is charged with interpreting the Ontario code, said schools had a duty to accommodate religious belief.
“Accommodation doesn’t equal endorsing or otherwise becoming entangled in religious practice,” Ms. Mandhane said. “Whether that requires prayer space in school, we’ve never said. What’s required is we need to reasonably accommodate a person’s beliefs.”
In an interview, she disputed the argument made by many protesters that the policy benefits only Muslims. She noted that Jews and Christians were already accommodated because their most important days of worship fall on the weekend, when schools are closed.
“In many ways, what we’re seeing in Peel is the edge where human rights and hyperdiversity connect,” Ms. Mandhane continued. “What Peel shows is that even in places with huge racial diversity, you can have people who identify with different communities but disagree about human rights issues.”
To the Peel school board and many Muslims in the district, the strife over religious accommodation is little more than Islamophobia.
At board meetings, protesters have screamed anti-Muslim epithets, while attacks against Muslims who speak out publicly have spread on social media, leading to the stationing of police officers at the meetings and outside schools. The imam who received the death threat also got an online message calling for his mosque to be burned.
During one fraught school board meeting, a man tore up pages of the Quran, stunning a community that had long prized its tradition of tolerance.
“These are people trying to fuel the fire and brew our ignorances,” said Rabia Khedr, executive director of the Muslim Council of Peel, which lobbied the school board in support of the students’ right to pray. “Religious accommodation is not at the exclusion of everybody. It’s at the inclusion of everybody.”
Anver Saloojee, a political-science professor at Ryerson University in Toronto, has another explanation. He noted that many of those speaking out against the religious accommodation policy were members of the Indian diaspora, including some vocal Hindu nationalists, suggesting that in some ways the battle in Canada mirrors South Asia’s historical Hindu-Muslim conflict.
But the groups opposing accommodation, which include people from a variety of races and religions, deny that. Indian-Canadian members of the groups say their concern has nothing to do with a country they left years and in some cases decades ago.
“My religion is Canadian; that’s what gives me the strength to stand up and fight now,” said Ram Subrahmanian, a founder of Keep Religion Out of Our Public Schools.
Shaila Kibria-Carter, 42, a finance manager of Bangladeshi descent, was born and raised in Canada and lives in the nearby town of Brampton. She said that as a Peel district high school student in the 1990s, she prayed in school on Fridays. So did her college-age son. There were never any class disruptions or complaints, she said.
“What these folks are doing is preaching hate,” she said. “We’ve lived in harmony with Sikhs and Hindus and white people all our lives, and now all of a sudden someone is in meetings ripping up a Quran.”