"I reckon it will become more and more popular as a phenomenon - equal marriage, gay marriage, call it what you like, around the world, not just in Europe, around the world," he said in an interview to BNS.
Bercow also rejected critics' claims that gay marriage would undermine man-woman marriage.
"I am in favor of equality and I cannot understand how anybody thinks that the value of a heterosexual marriage is somehow undermined because a gay couple have the chance to be married," he said. " My wife and I don't feel that our marriage is in any way threatened or undermined because a gay couple have the chance to be married. I think it is a great institution, and let's extend it," Bercow added.
In a historic vote earlier this month, the British Parliament adopted a bill on gay marriage, despite fierce opposition from members of Prime Minister David Cameron-led Conservative Party.
By taking this step, Britain is going to join 10 countries in the world which allow same-sex marriage.
Cameron said the plan to allow gay couples to get married in England and Wales "will make our society stronger" but the bill still has to overcome several parliamentary obstacles.
The British House of Commons voted in favor of the Marriage (Same Sex Couples) Bill, by 400 to 175, and it was adopted because of strong support from the Liberal Democrats and the opposition Labour Party. And only 127 out of 303 Conservatives voted in favor of the bill. 136 Conservatives voted against and 40 officially abstained or did not vote at all.
