Lawmakers in Thailand voted on Tuesday to approve a marriage equality bill, a move that puts the country on a clear path to becoming the first in Southeast Asia to legalize same-sex marriage.

Thailand’s Senate passed the bill on Tuesday afternoon, nearly three months after it was approved by the House of Representatives. The legislation would go into effect after it is reviewed by a Senate committee and the Constitutional Court and receives royal assent from the king, a formality that is widely expected to be granted.

The bill’s passage underscores Thailand’s status as a relative haven for gay couples in Asia. Only Taiwan and Nepal have legalized same-sex marriage. While India came close last year, the Supreme Court deferred the decision to Parliament.

In some Asian countries, gay sex is a criminal offense. Indonesia, where gay marriage is illegal, made extramarital sex illegal in 2022. In 2019, Brunei made gay sex punishable with death by stoning. It later said it would not carry out executions after widespread international protest.

Thailand’s bill calls marriage a partnership between two people age 18 and above, without specifying their gender. It also gives L.G.B.T.Q. couples equal rights to adopt children, claim tax allowances, inherit property and give consent for medical treatment when their partners are incapacitated.

The bill has been contentious since its first version was introduced over 20 years ago. While Thailand is one of the most open places in the world for L.G.B.T.Q. people, it is socially conservative in other ways.