Greek mafia (Greek: Ελληνική μαφία, romanized: Ellinikí mafía) is the colloquial term describing various large-scale organized crime elements originating in Greece or operated by Greeks. Indigenous organized criminal groups are well-established in the largest Greek urban centers, particularly in Athens.

Mafia groups in Greece take part in, among other crimes, racketeering, the illegal smuggling of oil, money laundering, cigarette smuggling, weapon and drug trafficking, kidnapping and murder. The domestic criminal syndicates additionally collaborate with Albanian, Romanian and Serbian mafia groups who operate in Greece.