Both services suffered a widespread outage lasting roughly 40 minutes on Tuesday affecting users in the United States, Asia, the UK and Australia.
The social media giant’s Instagram service was also briefly inaccessible.
On Twitter, Instagram said that it was aware of an outage and was working on a fix. There was no immediate statement from Facebook.
Facebook has about 1.25 billion users and Instagram has some 300 million.
News of the Facebook outage set rival social network Twitter alight.
Some users of Facebook had reported that the site was loading or responding slowly.