Users on both popular platforms were left unable to load the sites for hours, and thousands of people were unable to access their accounts entirely.
A Facebook spokesperson confirmed outages had hit its ‘family of apps’ and that the firm is working to fix the issue.
The global outage affected users in the US, UK, mainland Europe as well as parts of Australia and South America.
Issues were first reported early Tuesday morning and, although service resumed in some areas, many were still having trouble getting on the sites by 5pm ET.
It comes less than a day after Facebook Messenger crashed for users around the world.