The lights on the Mount Royal cross and Montreal City Hall will be turned off Saturday night to mark Earth Hour.
A number of other municipal buildings will follow suit, flicking their lights off between 8:30 and 9:30 p.m.
Mayor Denis Coderre is encouraging citizens and businesses to join the city in taking part in what is the tenth anniversary of the worldwide event aimed at raising awareness about climate change.
"In a spirit of global collaboration, it is essential that everyone contribute locally to adopt and promote best practices," Coderre said in a news release.
"That's why I'm inviting citizens, businesses, industries and Montreal institutions to join the international Earth Hour movement in large numbers."
Among other Earth Hour events taking place in Montreal is a performance by five youth choirs at Christ Church Cathedral.
The cathedral will be lit only by candles. The concert begins at 8:15 p.m.