Same-sex marriage has been legal in Austria since 1 January 2019. On 4 December 2017, the Constitutional Court ruled that the non-discrimination and equality provisions of the Constitution of Austria guarantee same-sex couples the right to marry. The decision took effect on 1 January 2019, making Austria the fifteenth country in Europe and the 24th in the world to allow same-sex couples to marry nationwide. Polling indicates that a majority of Austrians support the legal recognition of same-sex marriage.

Austria has also recognised same-sex registered partnerships since 1 January 2010, providing several, but not all, of the rights, benefits, obligations and responsibilities of marriage.

Unregistered cohabitation On 24 July 2003, the European Court of Human Rights published its decision in Karner v. Austria, which was submitted on 24 July 1997. The applicant, who died in 2000 while the case was pending, was taken to court in 1995 by his landlord who wanted to terminate the tenancy after Karner's same-sex partner died. Austrian law provided that family members had a right to succeed to a tenancy. While the case was initially dismissed by lower courts, the Constitutional Court of Austria ruled in favour of the landlord, saying the notion of "life companion" () was only applicable to persons of the opposite sex. The European Court of Human Rights considered this ruling to be in violation of the anti-discrimination provisions of the European Convention on Human Rights. Since this decision, cohabiting same-sex partners have been entitled to the same tenancy rights as unmarried cohabiting opposite-sex partners.

Registered partnerships Discussions in 2004–2006 Between 2003 and 2007, the Social Democratic Party (SPÖ) and the Greens were in opposition while the government was led by the conservative Austrian People's Party (ÖVP). Both centre-left parties called for the recognition of same-sex unions. First, in June 2004, the Greens proposed a civil pact () modelled after the French civil solidarity pact. In December 2004, the SPÖ adopted a major policy decision on the issue of equal treatment for same-sex couples. In addition to calling for the introduction of registered partnerships, the party supported the investigation of opening marriage to same-sex couples. In May 2005, the Greens became the first major party to expressly call for the legalisation of same-sex marriage. The Greens praised the June 2005 referendum in Switzerland legalising registered partnerships and called for equal rights in Austria. In April 2006, the Vienna branch of the SPÖ followed the Greens in explicitly calling for the legalisation of marriage and adoption for same-sex couples.

Passage of legislation in 2009 Following the October 2006 election, the conservative Schüssel Government was succeeded by an SPÖ-ÖVP grand coalition on 11 January 2007. In the "Perspectives" paper released by the People's Party on 1 October 2007, the coalition announced its support for registered partnerships (, ) similar to the Swiss model. An agreed draft was released in late October 2007. It would have given couples in registered partnerships nearly the same rights as married couples, with the exception of adoption rights. The registered partnership bill, based on the Swiss model, was planned to be introduced to the Austrian Parliament in September 2008; however, as the coalition of Social Democrats and the Austrian People's Party broke apart and early elections were scheduled for 28 September 2008, progress was delayed. The two parties saw considerable losses in the election but continued their grand coalition under Chancellor Werner Faymann.

In February 2009, Interior Minister Maria Fekter set up a working group, inviting delegations from Austrian LGBT rights organizations, including the Lambda Legal Committee (RKL; ), Pink and Lavender Panthers () as well as the Linz, Salzburg, Tyrol and Vienna branches of the Homosexual Initiative (HOSI; ), to hold talks on the issue of partnership recognition for same-sex couples. Fekter announced that a registered partnership bill would be introduced and enacted in autumn 2009 and would become effective on 1 January 2010. On 12 October 2009, the Greens urged the government to keep to its promise of having registered partnerships implemented by January 2010, with Green justice spokesman Albert Steinhauser saying that "time was running out" for the proposed law. The party also called for opening marriage to same-sex couples. The next day, Minister of Justice Claudia Bandion-Ortner announced that a registered partnership law would be announced "in a few weeks". She said that such a law was in the process of being drafted, with some aspects of it still being under contention. A particular area of contention was whether registered partnerships should include a ceremony at the Standesamt. Bandion-Ortner: Einigung in "wenigen Wochen" , Der Standard, 13 October 2009

On 11 November 2009, Bandion-Ortner presented a bill, which was rejected by the SPÖ because the bill did not include ceremonies. On 17 November 2009, the Faymann Government finally approved the registered partnership bill proposed by the Ministry of Justice. Registered partnerships provide equal rights in labour, immigration, pension, tax, and civil law to same-sex couples as marriage does to opposite-sex couples. It also allows registered partners to take a common surname. The bill was passed on 10 December by the National Council in a 110–64 vote. The two governing parties voted in favour, while the Freedom Party of Austria (FPÖ) voted against and the Alliance for the Future of Austria (BZÖ) and the Greens voted mostly against. The Greens considered it a step in the right direction, but thought it did not go far enough. It was passed by the Federal Council in a 44–8 vote on 18 December. On 30 December, the law was published in the , and took effect on 1 January 2010. The first four partnerships were registered in Vienna on 4 January 2010.

+ 10 December 2009 vote in the National Council Party Voted for Voted against Absent (Did not vote) Social Democratic Party – Austrian People's Party – Freedom Party – Alliance for the Future of Austria The Greens – The Green Alternative Total 64 9

Lambda Legal Committee noted at the time the law was passed that there were 72 differences between registered partnerships and marriage. An opposite-sex couple applied for a registered partnership in February 2010, despite the legislation being created specifically for same-sex couples. The issue was mooted in December 2017 when the Constitutional Court ruled that the restriction of registered partnerships to same-sex couples was discriminatory and mandated that opposite-sex couples have the right to enter into registered partnerships from 1 January 2019.

Expansion of partnership rights In January 2013, the Constitutional Court ruled that the registered partnership law was partially unconstitutional, broadening the rights of registered partners. On 19 February 2013, the European Court of Human Rights ruled in X and Others v. Austria that a partner in a same-sex union has the right to adopt his or her partner's biological child. On 5 July 2013, the Austrian Parliament passed the Adoption Law Amendment Act 2013 (), allowing stepchild adoption by same-sex couples. The law entered into force on 1 August 2013.Adoptionsrechts-Änderungsgesetz 2013 , Austrian Parliament In January 2015, the Constitutional Court found the existing adoption laws to be unconstitutional and ordered the laws to be changed by 31 December 2015 to allow joint adoption by same-sex couples. On 30 October 2015, Justice Minister Wolfgang Brandstetter announced that the ban would no longer be enforced from 1 January 2016, thus allowing the court's decision to automatically abolish the joint adoption ban.

In June 2013, in the run-up to that year's election, the newly founded liberal party NEOS – The New Austria published a policy position paper including support for equal rights for registered partners, including adoption rights. The SPÖ-ÖVP coalition government continued following the elections. Although the SPÖ had campaigned on an LGBT rights platform, the coalition agreement did not include any measures to expand LGBT rights, due to opposition from the conservative ÖVP.

In late September 2016, the ÖVP-led ministries agreed to remove two prominent differences between registered partnerships and marriages. These were allowing partnerships to be registered at the Standesamt rather than at the district authorities (), and granting registered partners a regular family name () rather than a last name (), which was specifically created for partnerships. Following approval by the Council of Ministers on 22 November 2016 and by Parliament on 15 December, the law took effect on 1 April 2017. The Deregulation and Adaptation Act 2016 (), which included various other unrelated changes such as amendments to the gun law, was approved by both governing parties and NEOS and opposed by the FPÖ, the Greens and Team Stronach.Deregulierungs- und Anpassungsgesetz 2016 - Inneres (1345 d.B.) , Austrian Parliament Opposition parties criticised mixing unrelated legal matters in one law.

Statistics 4,927 same-sex couples had entered into registered partnerships by the end of 2025, mostly in Vienna.

+ Number of partnerships registered in AustriaState2010201120122013201420152016201720182019202020212022202320242025TotalBurgenland127710818118200112078Carinthia1720122223222222143324222192Lower Austria106495242385950625487179161518602Salzburg3217192024222538191455534243Styria74464635516446535411118981314543Tyrol4523233328363743446544668351Upper Austria58434132364258605187971392476Vienna349225179159185167215227198654552646069542,313Vorarlberg1237159101613226163114129Total705433386368402423477529464110831031061121201064,927

Different-sex couples have been allowed to enter into registered partnerships since 1 January 2019. In 2019, 1,135 opposite-sex couples entered into such a union, followed by 1,173 more couples in 2020.

Same-sex marriage

Background Austria indirectly saw its first same-sex marriage in 2006 when the Constitutional Court granted a transgender woman the right to change her legal gender to female while remaining married to her wife. The court invalidated a regulation that required married transgender people to divorce before their new gender was legally recognised.

On 20 November 2013, the opposition Greens introduced a bill to the National Council to legalise same-sex marriage. It was sent to the Judiciary Committee on 17 December 2013 but was delayed by the ruling SPÖ-ÖVP coalition government. The bill was due to be debated in autumn 2014. In 2013, a same-sex couple, married in the Netherlands and resident in Austria, who wanted to get married under Austrian law to remove uncertainties regarding their marital status, filed a case with the Constitutional Court, but it was dismissed on 12 March 2014.