The European Union and Japan filed a WTO complaint two years ago, arguing that a section of the province's green energy program requiring made-in-Ontario parts for wind and solar farms breaches international trade law.
McGuinty dismissed the complaints Tuesday, saying that the requirements have not prevented companies from other countries from trying to participate in Ontario's green energy economy.
He said Ontario has secured $27 billion worth of investment from Korea, China, the U.S., France and Germany in renewable energy projects.
McGuinty said Ontario is creating thousands of jobs and manufacturing opportunities, and he will continue to "stand up for economic growth and jobs here."
The WTO has given its ruling to the parties involved in the dispute, but has not actually made it public, so McGuinty said he can't really comment on any details.
The Progressive Conservatives said the WTO ruling is proof the green energy act, which pays generous premiums for wind and solar-generated electricity, should be withdrawn.
"This means there’s absolutely no way the Liberal government will be able to come close to its target of 50,000 green jobs being created," said PC energy critic Vic Fedeli.
"It’s just the latest in a series of failures for the (feed-in-tariff) program, and it’s time to scrap it."
The New Democrats urged McGuinty to appeal the WTO ruling when it is publicly announced sometime next month.
"The federal and provincial governments should be looking for options to preserve Ontario content if the WTO appeal were to fail," said NDP energy critic Peter Tabuns.