English-language universities in Quebec are pushing back on a plan that will raise tuition fees and mandate French proficiency for out-of-province students.
McGill University in Montreal called the move "catastrophic", while Concordia University said it was "disappointed" in the changes.
Both universities are concerned they will lose students.
The plan by Quebec's government is set to take effect next year.
The changes, made public in a letter published Thursday by Quebec's higher education minister Pascale Dery, will hike tuition for out-of-province students by 33%.
They will also require that 80% of students from outside Quebec reach an intermediate level of French by the time they graduate, and universities would face financial penalties if that target is not met.
Universities will also see a larger chunk of international student fees going directly to the province instead of their operating budget.
In the letter, Ms Dery told Quebec's three English-language universities - McGill and Concordia in Montreal, and Bishop's in Sherbrooke - that the changes are designed to balance funding received by English and French universities in the province.
She said it would also mean Quebec would spend less money subsidising students from the rest of Canada and help preserve the French language.
McGill University's President Deep Saini criticised the plan at a news conference on Thursday. He said it was "incoherent" and based on "impressions and emotions, rather than evidence-based decision-making".
He added his university had not ruled out moves like opening another campus outside of Quebec or filing a potential lawsuit.
Meanwhile, Concordia University President Graham Carr told the Montreal Gazette that he believed the plan would shrink the size of its student body and hurt Quebec's reputation.
Both universities said the changes could cost them C$150m ($111m; £88m) annually. McGill University added it may have to cut up to 700 jobs as a result.
The overhaul to higher education in Quebec comes amid other policies aimed at preserving the province's French heritage and language, which Quebec has long-sought to protect as the French language declines in the rest of Canada.
In June, Quebec passed a law called An Act respecting French, which established the language as the sole official and common language in Quebec.
