The Marriage Equality bill has passed the House of Representatives with all the proposed amendments defeated.
Now the Governor-General needs to give it Royal Assent.
Attorney-General George Brandis has some important information for people wanting to get married.
"The right to marry in Australia will no longer be determined by sex or gender. Marriage will now be defined in the Marriage Act 1961 as the 'union of two people to the exclusion of all others, voluntarily entered into for life'. Same-sex couples now have the same rights under the Marriage Act as all other couples," Senator Brandis says.
"These historic reforms will commence on Saturday, December 9, 2017. As from Saturday, same-sex couples will be able to lodge a Notice of Intended Marriage to commence the one month minimum notice period required before the solemnisation of marriages under the Marriage Act."
In speaking to the house before the bill was passed, Prime Minister Malcolm Turnbull said: "What a day! What a day for love, for quality, for respect! Australia has done it."
"The Parliament has got on with it and we have voted today for a equality, for love, it is time for more marriages, more commitment, more love, more respect, and we respect every Australian who was voted, those who voted yes, and those who voted no, this belongs to us all, this is Australia!"
"Let's do it, let's finalise the deal right now!"
Opposition Leader Bill Shorten says: "Australia, we are going to make marriage equality a reality in minutes. The Australia of tomorrow begins with what we do today. At long last, LGBTIQ Australians will be equal under the law."
"And those of in Parliament privileged to serve, we understand that we do so with humility. The humility to recognise that the passage of this law does not in essence belong to us, but the credit for the passage of this law belongs to all Australians and I say to those who voted no, I recognise that now is the time for healing, to put this debate behind us."
"And when this law is passed, we should declare that we are no longer a nation of people who voted no. Or people who voted yes. We are simply Australians one and all. And I said to LGBTIQ Australians in particular, you have given us a gift.
“This Parliament, when we passed the marriage equality law, is not a gift from us to LGBTIQ Australians,equality is never a gift to be given. Equality isn't in our legal birthright of every Australian and this equality is long overdue."
"I say the gift that LGBTIQ Australians have given all of us is that we are a nation who includes all of our people, who values all relationships and all families, that we are a better nation altogether. So, as it is written that there is a time for everything, and a season for every activity under the heavens, it is now time to heal. A time to build, a time to love, a time to love, and is now at last a time for marriage equality."
Greens MP Adam Bandt says: "What a big day for love because, despite the years of bigotry and hate, and despite the years of violence and lies, and the ignorance and fear, love has won and it is time to pop the bubbly. I'm going to keep it short and sweet. Because it is time to let the bells ring and let the people sing because love has won!"
In the Senate, 57 senators spoke for nearly 28 hours on the same-sex marriage debate.
The House of Representatives has devoted 28 hours (so far) to the debate and 118 MPs have spoken.