Mayor Denis Coderre said he was showing solidarity with the Russian gay and lesbian community at a rainbow flag raising ceremony at City Hall this afternoon.
Montreal joins several other Canadian cities to fly the international symbol of gay pride and gay rights for the duration of the Sochi games.
Coderre said the flag-raising was meant to send a message to the Russian government.
He believes that as the mayor of an Olympic city, he felt it was necessary for him to speak out on the issue.
"I want to give my best to our team and to say that we are totally behind them, but my role also is to send some messages because those [Russian anti-gay] laws don't represent the values of Olympism," he said.
He wants other Canadian cities to follow suit.
So far, many have, including Vancouver, Edmonton, Ottawa, Laval, Quebec City and St. John's, Newfoundland.
Toronto is also flying a rainbow flag outside its city hall, although its mayor Rob Ford was initially opposed to it. He eventually changed his mind after talking to several Toronto councillors.