Same-sex marriage is set to be legalised in Australia by the end of 2017 after 61.6 per cent of respondents in the country's Marriage Law Postal Survey voted Yes.
But for 25 countries around the world it’s already a right - and has been in several countries for more than a decade.
In most cases marriage equality has been legislated by parliaments, but in several cases constitutional courts have forced the government's hand.
Ireland remains the only country to have put the issue to a referendum.
More than 840 million people now live in countries where same-sex marriage is legal.
2001 – The Netherlands
The Netherlands was the first country to pass legislation to allow same-sex couples to legally marry, divorce and adopt children.
The law passed by a three-to-one margin.
2003 – Belgium
Belgium’s parliament voted to allow same-sex marriage in 2003, with legislation in 2006 granting same-sex couples the right to adopt children.
2005 – Spain and Canada
In 2005 Canada became the first country outside of Europe to legalise same-sex marriage. Parliament passed legislation after a steady march of court rulings had legalised the practice in the majority of the country’s provinces.
The Conservative Party attempted to repeal the legislation one year later but was defeated.
Spain’s parliament narrowly passed some of the world’s most liberal marriage equality laws in 2005, extending full rights to same-sex couples.
The move saw protests from Catholic officials and brought large crowds to the streets in Madrid.
2006 – South Africa
South Africa’s parliament legislated for same-sex marriage in 2006, codifying a 2005 court decision which found that restricting marriage to heterosexuals was discriminatory and unconstitutional.
It remains the only country in Africa where same-sex marriage is lawful. The legislation passed with overwhelming support.
2009 – Norway and Sweden
Norway replaced its civil union laws with full marriage and adoption rights in 2009. Parliament was split over the issue.
In 2017 the Norwegian Lutheran Church, to which most Norwegians belong, voted to authorise its pastors to conduct same-sex marriage.
Sweden’s parliament passed same-sex marriage laws decisively in 2009, also replacing earlier civil union laws. The Church of Sweden allows clergy to officiate ceremonies.
2010 – Portugal, Iceland and Argentina
Portugal legalised same-sex marriage in 2010 through a parliamentary vote. In 2016 parliament overturned a presidential veto and granted same-sex couples the right to adopt.
Iceland’s parliament unanimously passed same-sex marriage legislation in 2010. Couples were already able to adopt.
The country’s Prime Minister, Jóhanna Sigurðardóttir, was one of the first to utilise the legislation, marrying her partner, Jónína Leósdóttir.
Argentina’s parliament narrowly passed same sex-marriage laws in 2010, following several regional areas passing civil union laws.
The law sparked outcry from Catholic groups in the country as it became the first in South America to legalise same-sex marriage.
2012 – Denmark
Denmark passed same-sex marriage legislation in 2012. Couples already had the right to register as partners and adopt children.
2013 – France, Brazil, Uruguay and New Zealand
New Zealand became the first country in the Asia Pacific to legalise same-sex marriage when parliament comfortably passed the law in 2013. The law also allowed couples to adopt.
France legalised same-sex marriage and same-sex adoption in 2013, a move which attracted hundreds of thousands of protesters and counter-protesters.
Uruguay decisively passed same-sex marriage legislation in 2013. Couples already had the right to adopt.
Brazil became the first country to legalise same-sex marriage not through legislation, but with a court ruling.
The National Justice Council ruled in 2013 that civil registrars must offer same-sex marriage services, after several regions had already legislated for legalisation.
2014 – The United Kingdom, excluding Northern Ireland
In 2013 British parliament passed a law which would legalise same-sex marriage in England and Wales the following year. In 2014 the Scottish parliament passed a similar bill.
Northern Ireland has not passed same-sex marriage legislation.
The Church of England remains opposed to same-sex marriage, despite ongoing internal debate over the issue.
The UK has performed hundreds of same-sex weddings in Australia for dual citizens.
2015 – Ireland, United States and Luxemburg
In 2015 the Supreme Court of the United States declared that the constitution protected the rights of citizens to marry, regardless of gender.
The divided Obergefell v. Hodges ruling instantly legalised same-sex marriage across all 50 states, several of which had already legislated the issue themselves.
It was the same year that Ireland became the first country to legalise same-sex marriage by popular vote.
The majority Catholic country voted in support of same-sex marriage with a majority of 62 per cent.
Luxembourg’s parliament overwhelmingly supported same-sex marriage and adoption legislation in 2014, which came in to force on January 1, 2015.
Less than four months after the law came into effect, Prime Minister Xavier Bettel married his partner, Gauthier Destenay.
2016 – Colombia and Greenland
In 2016 Colombia’s top court ruled that the country’s constitution guaranteed the right to same sex marriage for LGBT+ citizens.
Greenland’s parliament unanimously voted to adopt the marriage and adoption legislation of its parent country, Denmark, in 2015. The legislation came into effect for 56,000 Greenlanders in 2016.
2017 – Finland, Slovenia, Malta, Germany
The Finnish parliament passed same-sex marriage legislation in late 2014, and in 2017 rejected a citizens' petition to repeal the law.
The law came into effect this year. Every Nordic country now has legal same-sex marriage.
In Slovenia, civil partnerships have been recognised since 2006, with the same-sex marriage bill being approved 10 years later in 2016. The legislation officially came into effect in 2017.
Malta has allowed same-sex couples to marry since a near-unanimous approval of the bill in July 2017, three years after a law was passed permitting civil partnerships in the predominantly Catholic country.
German MPs voted to legalise same-sex marriage in a snap poll in June 2017. It became law the following October.
Pending – Taiwan, Australia
In 2017 Taiwan’s top court issued an ultimatum to the parliament: legislate same-sex marriage within two years or it will become legal regardless.
Even before the ruling, President Tsai Ing-wen promised to legislate for same-sex marriage.
Australia found out on November 15, 2017 that 61.6 per cent of voters were in favour of legalising same-sex marriage, while 38.4 per cent voted against it. The Coalition government has pledged to introduce a private member’s bill allowing same-sex couples to marry before the end of the year.
Registered partnerships (with similar rights to marriage) are recognised in: Austria, Croatia, Cyprus, Greece, Hungary and Italy.