Hydro-Québec says high winds are to blame for knocking out power for at least 155,000 customers Thursday afternoon.
Outages were reported in the Outaouais, on the South Shore, in Laval, the Laurentians, the Eastern Townships and Central Quebec.
Environment Canada issued a wind warning for much of Quebec on Thursday, with wind gusts up to 90 kilometres per hour expected to blow through the province.
The winds blew down utility poles and wires, said Hydro spokesman Jean-Philippe Rousseau.
More than 9,000 Montreal customers are affected by the power outage, most of them on the West Island.
Rousseau says the situation is slowly improving since outages were first reported Thursday afternoon.
Hydro crews are being dispatched to various regions to fix the problem.