The suit was filed with the Ontario Superior Court of Justice by law firm Sutts, Strosberg LLP.
The plaintiff, Dominik Konjevic, is seeking $400 million in compensatory damages, $10 million in punitive damages and an injunction prohibiting UberX from continuing to operate in the province.
The lawsuit alleges Uber violated parts of the Highway Traffic Act, causing the plaintiff and others in the taxi industry to suffer damages.
The suit is said to be on behalf of all Ontario taxicab owners, drivers and brokers, as well as limousine owners, drivers and licensed service companies.
"The Plaintiff alleges that Uber X and Uber XL has created an enormous marketplace for illegal transportation in Toronto," said Jay Strosberg, a lawyer with Sutts, Strosberg LLP.
An Ontario judge recently ruled in Uber's favour in a case in which the City of Toronto alleged the ride-sharing company was violating municipal bylaws. Superior Court Judge Sean Dunphy ruled earlier this month there was "no evidence" Uber is operating as a taxi broker or that it breached Toronto city bylaws.
But this latest class action lawsuit alleges that UberX and UberXL, services in which drivers use their own cars or SUVs to transport passengers, are in violation of the portion of the Highway Traffic Act that governs taxi and limo businesses in Ontario.
It also alleges that the defendants were unjustly enriched when they collected a portion of the UberX and Uber XL fares which were in contravention of Ontario's Highway Traffic Act that deals with transporting passengers for compensation.
Uber, which began offering its services in London, Hamilton, Waterloo and Guelph on Thursday, referenced the previous legal ruling in its response.
"This protection suit is without merit," Uber said in a statement. "As we saw from a recent court ruling in Ontario, Uber is operating legally and is a business model distinct from traditional taxi services."