Legislation passed parliament on December 7, around a month after a majority of Australians voted in favour of legalising it in a voluntary postal survey.
Same-sex marriage ceremonies are taking place across the country, as Australia celebrates the first official day of marriage equality.
At a minute past midnight, Diana and Deanne Ribeiro made their marriage official in the Melbourne suburb of Balaclava.
Around 60 guests counted down to midnight before the pair took their vows in the same place as their commitment ceremony five years earlier.
According to Diana it couldn't have gone any better.
"It was just magical," she told SBS News.
"To be able to come back here and redo our vows and actually make it legal and finally have equality in Australia is amazing."
Deanne said the couple was looking forward to their future together.
"We’re just so excited to be equal like everyone else in Australia."
Athletes Craig Burns and Luke Sullivan timed their wedding in Tweed Heads, New South Wales so their marriage would become official just minutes after midnight on Tuesday morning.
Also wanting to be part of history, Rebecca Hickson will marry her partner of nine years Sarah Turnbull, planning to be one of the first couples to tie the knot in a morning ceremony in Newcastle.
It’s the second time around for the pair, having already held a ceremony three years ago.
“Now we get to declare our love for each other again and have it recognised as a real union," Rebecca said.
Almost a month later, legislation cleared parliament after a long debate.
Same-sex couples were quick to lodge their intentions to marry. While some were granted exemptions to the four-week waiting period, Tuesday is the first official day ceremonies can take place.
Melbourne couple Ron Van Houwelingen, 50, and Antony McManus, 53, said no country should ever have to go through what Australia did to legalise gay marriage, calling it “horrendous”.
The pair will hold their wedding where they first met as performing arts students three decades ago at the former Prahran College of TAFE's David Williamson Theatre.
They have already held more than a dozen commitment ceremonies, though that still hasn’t been enough time for Ron.
"I suppose it's been a wedding planned for 30 years but we've had really a month to get things together," he said.
"It's been quite hectic trying to organise that in such a short amount of time."