"As of this morning, the Facebook community is now officially 2 billion people!" co-founder and chief executive Mark Zuckerberg wrote in a post on his Facebook page marking the milestone.
"We're making progress connecting the world, and now let's bring the world closer together," he wrote. "It's an honor to be on this journey with you."
Naomi Gleit, a vice president at the internet giant, credited millions of small communities at Facebook for helping drive growth.
More than a billion people take part in "groups" at Facebook each month and more than 800 million people "like" something at the social network on an average day, she added.
Founded in 2004, Facebook hit the billion-user mark five years ago.
Meanwhile, the social network announced that it deleted about 66,000 posts a week in the last two months in an effort to crack down on what it deems to be hate speech.
The company said in a blog post that deleting posts can "feel like censorship", but that it is working on explaining its process better and improving its enforcement of hate speech.
Facebook defines hate speech as attacks on people based on their race, sexual orientation and other "protected characteristics".
As part of that effort, Facebook says it plans to hire an additional 3,000 people in the next year to review posts. That is on top of the 4,500 people it currently has reviewing posts.