Supporters gathered in central Athens as the vote was announced.
Greece has legalised same-sex marriage - becoming the first Orthodox Christian country to do so.
The law passed by 176 to 76.
It also allows adoption, but doesn't cover gay men who want a biological child through a surrogate.
There was opposition to the bill from the Church - and some far-right parties.
Supporters gathered in central Athens as the vote was announced:

Man Hospitalised After Alleged Assault In Dublin
Gardaí Believe Drug-Related Activity Was Central To Waterford House Fire
Widespread Disruption As Public Sector Strikes Get Underway
PrepayPower Becomes Second Energy To Supplier To Announce Winter Price Freeze
Two Adults And Two Children Die In Waterford House Fire
Five-Year National Drug Strategy Set To Be Launched
Number Of Fatalities At Scene of Fire In Waterford
Daniel Kinahan Set To Apply For Bail