A symbolic motion promising to oppose any bills that would restrict people's freedom of expression and religion in public places passed unanimously in the legislature, with support from Premier Kathleen Wynne and all three parties.
Quebec's charter aims to impose restrictions on religious clothing and symbols on every public servant, including judges, police, teachers and hospital workers.
The vote reaffirms Ontario's commitment to respect and celebrate diversity, which builds a strong economy, Wynne said after the vote.
"We are sending the world a message that our differences don't divide us, they unite us," Wynne said.
Veteran Liberal Monte Kwinter, who introduced the motion, said it's tarnishing Canada's image abroad and Ontario must show the world that it won't follow in its neighbour's footsteps.
But he said he's not trying to stir things up with Quebec.
"I don't want to interfere in their internal politics — that's their business," said Kwinter, a former cabinet minister who has spent 28 years in the legislature.
"But it immediately raises a question: if this is happening in Quebec, is this going to happen in Ontario?" he said.
"And what I want to do — and my motion is saying — that it absolutely is not something that we would allow to happen. And it's as simple as that."
His motion received a "tremendous" response from across the country, Kwinter said.
He said he got an email urging the government to put up a big sign at the Ontario-Quebec border that says: "Welcome to Ontario. Come as you are."
But not all the feedback was positive, he said.
"I'm certainly getting the bad," said Kwinter. "I'm getting people who call me and say, 'This is ridiculous. If people come to Canada, they should come and look like Canadians, act like Canadians and be Canadians' — whatever that means."
Many Jewish families moved to Toronto when the Parti Quebecois was in power 30 years ago, over concerns about separation and the introduction of restrictive language laws, said Kwinter, who is Jewish.
It could happen again if the charter passes in Quebec, he said.
The Liberals also launched a website called "One Ontario," lauding their support for diversity.
New Democrat Jagmeet Singh said the legislation has become a big topic in the Sikh community as well, dominating local radio talk shows.
He said it's important for him to carry a kirpan — a religious ceremonial dagger — in the legislature.
"When I wear the kirpan day to day, it reminds me of my oath, that it's my duty as a Sikh to stand up for the rights of all people, to stand up against injustice and to protect people and their freedoms," he said.
"That's an important belief for me and it's important for me to express that daily."
But the motion isn't enough, he said.
There should be more concrete protection of rights, such as allowing Sikhs to wear kirpans in courthouses, as well as accommodate people of other faiths, said Singh, a former lawyer.
Progressive Conservative Leader Tim Hudak also slammed the charter, saying the government has no right to tell people that they can't wear a cross or a star of David.
"It's not the place of government to restrict those things and that runs against the great values that we have as Canadians that attracted us here in the first place," he said.
Ontario grappled with religious accommodation in 2005 when it was poised to become the first Western jurisdiction to use Shariah law to settle Muslim family disputes.
Then-premier Dalton McGuinty decided to ban all religious arbitrations in the province, including existing tribunals that had been used for years by Christians and Jews.