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:

Vacuum-Packing Machine Lid Killed Worker As Kildare Town Firm Faces Court Over Second Fatality
Water Test Failure Disrupts On-Base Military Training At Curragh Camp
Government Told Grok Clothing-Removal Feature Has Been Disabled Worldwide
Kildare North TD Says He Acted Immediately To Repay Pension Overpayment When It Came To Light
Maynooth Study: Pet Loss Causes The Same Level Of Grief As Losing A Loved One
Kildare TD James Lawless Pays Back Following Pension Error While Martin Heydon Unaffected
Up To €1,000 Available For Kildare Parent And Toddler Groups
Driving Instructor Says Faded Road Markings In Naas Linked To Learner Drivers Failing Tests