Facebook has more than 200 million members worldwide.
Facebook has sold a 1.96% stake for $200m (£126m) to a Russian internet firm, a move that values the social networking website at $10bn.
Facebook boss Mark Zuckerberg said he had been impressed by Digital Sky Technology's (DST) "impressive growth and financial achievements".
DST has investments in a number of internet firms across Russia and Eastern Europe.
US-based Facebook has more than 200 million global members.
Facebook said DST would not be represented on its board or hold special observer rights.
"This investment demonstrates Facebook's ongoing success at creating a global network for people to share and connect," added Mr Zuckerberg, Facebook's chief executive.
"A number of firms approached us, but DST stood out because of the global perspective they bring."
DST's internet businesses account for more than 70% of all page views on Russian language websites.
It has investments in sites including Mail.ru, Forticom and vKontakte.
The deal comes two years after Facebook sold a 1.6% stake to Microsoft for $240m.