After a 13-hour debate, the majority, including a party from the government coalition, voted in favor of a bill that would mean the country withdrawing from the so-called Istanbul Convention.
Critics say the convention promotes a deviant gender ideology. Many also argue that Latvian law already protects women well enough.
The process against the vote was started by the opposition in September. The proposal was then supported by the populist ZZS, which thus went against the two other governing parties in the coalition.
On Wednesday evening, around 5,000 demonstrators gathered outside the parliament building to protest the law, including Prime Minister Evika Silina.
"Those who have been brave enough to ask for help are now seeing their experiences used as political bludgeons," she writes on X.
On Thursday, about 20 people gathered to show their support for the decision.
Latvian President Edgars Rinkevičs will now review the law.
