Thailand is expected to become the first country in Southeast Asia and the third in Asia to legalise same sex marriage.
The Senate approved the marriage equality bill on Tuesday 18 June with 130 votes in favour, four against, and while 18 members abstained.
The bill was met with overwhelming support by the lower house in March.
Under the new legislation, the Civil and Commercial Code will define in gender-neutral terms as a partnership between two individuals.
Same sex couples will also have the same inheritance, medical, and adoption rights as heterosexual marriages.
The legislation now requires the royal assent of King Vajiralongkorn, a formality that is widely expected to be granted.
It will come into effect 120 days after its publication in the Royal Gazette, which would allow the first same sex weddings to take place later this year.
Thailand has a reputation as a relative haven of safety and tolerance for LGBTQIA+ people in Asia. Same sex relations are criminalised in neighbouring Malaysia and Myanmar.
According to a 2023 survey by Pew Research Centre, 60 percent of adults in Thailand said they support legalising same sex marriage.
However, activists have struggled against conservative attitudes and governments for decades to advance the rights of LGBTQIA+ people.
Thailand still offers no legal protections for transgender people nor legal gender recognition.
Amnesty International Thailand Researcher Chanatip Tatiyakaroonwong said, “By potentially becoming the third place in Asia to legalize same-sex marriage, Thailand has the opportunity to set a bold example for LGBTI people’s rights in this region.”
“These bills and the debates in Parliament over them represent a moment of hope for LGBTQI people’s rights in Asia, even though there is still much to be done for their full protection.”
Taiwan became the first country in Asia to recognise same sex marriage in 2019 and Nepal the second in 2024.