Greece is the first Orthodox Christian-majority country to legalize same-sex marriage.
Same-sex couples will now be legally allowed to adopt children, following a vote in parliament on Thursday (176 to 76).
Prime Minister Kyriakos Mitsotakis said the new law would “boldly tackle deep inequalities”.
However, the country was divided due to fierce resistance led by the powerful Orthodox Church. Their supporters held a protest rally in Athens.
In the capital’s Syntagma Square, many people carried banners, carried crosses, read prayers and sang Bible verses.
The head of the Orthodox Church, Archbishop Ieronymos, said the measure “undermines the social cohesion of the homeland.”This bill needed a simple majority to pass the 300-member Congress.
Mitsotakis supported the bill, but it would need support from opposition parties to pass, and dozens of members of his centre-right ruling party opposed it.