Twenty-two years after homosexuality was decriminalised, 1.2 million people voting for the social reform in a referendum on Saturday.
Marriage ceremonies for gay couples will take place in Ireland by the autumn following the country’s resounding Yes vote.
The 62 per cent vote in favour heralds a major shift in values for a country traditionally held up as a bastion of Catholicism and socially conservative lifestyles.
The vote effectively ratifies the Marriage Equality Bill 2015 which was passed by Ireland’s parliament, the Dail, by overwhelming majorities back in March.
This new law will be brought in before the parliament breaks up for the summer, which means the first marriages are unlikely to take place until September.
Taoiseach Enda Kenny praised voters, including the tens of thousands who registered for the first time and many who travelled home to cast ballots.
He said: “The decision makes every citizen equal and will strengthen the institution of marriage for all existing and future marriages. All people now have an equal future to look forward to.”
Prime Minister David Cameron took to social media to praise the historic reform.
“Congratulations to the people of Ireland, after voting for same-sex marriage, making clear you are equal if you are straight or gay,” he said.
Amnesty International said the historic vote means Northern Ireland is now the only part of the UK and Ireland not to extend civil marriage rights to same-sex couples.
Meanwhile Australian Prime Minister Tony Abbott has said his country would not follow Ireland’s lead and hold a referendum on same-sex marriage, adding that any decisions would be made by parliament.
One of Ireland’s most senior Catholic clerics has called for the church to take a “reality check” in the wake of the result.
Diarmuid Martin, the archbishop of Dublin, said the Church in Ireland needed to reconnect with young people.
He said: “It’s very clear that if this referendum is an affirmation of the views of young people, then the church has a huge task in front of it to find the language to be able to talk to and to get its message across to young people, not just on this issue, but in general.”
A host of celebrities welcomed the vote result, on Twitter.
US talk show host Ellen DeGeneres shared with her 43.6 million followers her support for the vote. Actor Russell Crowe also wrote on Twitter: “Dear Ireland, you are even more amazing.”
Meanwhile U2 frontman Bono celebrated Ireland’s vote for gay marriage during the band’s current US tour.
On stage in front of thousands in Phoenix, the Irish singer dedicated Pride (In The Name Of Love), to mark the historic day.
“It’s a moment for us to thank the people who bring us peace to our country,” he said.
“We have peace in Ireland today . . . and in fact on this very day we have true equality in Ireland.
“Millions turned up to vote on Saturday to say love is the highest law in the land – love.”