The Marriage Act 2015 has been signed into law, and the move has been praised across the globe.
The Presidential Commission signed the act into law last night.
It now needs a commencement order from the Minister for Justice, to allow full same-sex marriages to begin - within weeks.
It makes Ireland the first country to put same-sex marriage in place by popular vote.
Director of the Gay and Lesbian Equality Network Brian Sheehan - who's in Athens at an LGBT conference says - it gives other campaigners hope: