The button will let people hide comments on their Facebook pages and also provide feedback about them. The feature is only for use in the US at the moment.
The move has long been anticipated – and demanded by users – but the social network says it is not a ‘dislike’ button.
“We are exploring a feature for people to give us feedback about comments on public page posts. This is running for a small set of people in the US only,” the company said in a statement.
When the downvote button is clicked, the selected comment is hidden. Users can then decide whether to flag a post as ‘offensive’, ‘misleading’ or ‘off-topic’.
Previously, Facebook’s creator Mark Zuckerberg has ruled out adding a dislike button to the social media giant’s site, claiming that would not help the kind of online community the company is trying to create.