The Green Party has voted to go into government with Fine Gael and Fianna Fáil.
It clears the way for the Fianna Fáil / Fine Gael / Greens government to be formed, after the other two parties also backed the deal.
Fianna Fáil leader Micheál Martin is now expected to be elected as Taoiseach by the Dáil tomorrow at a special sitting in the Convention Centre in Dublin.
The Greens had needed a two-thirds majority of members to approve the deal in a postal ballot.
Almost 1,900 members of the party cast their votes - with the final result 76% to 24% for no.
It was earlier confirmed that members of Fine Gael had backed the deal overwhelmingly, with 80% voting yes and 20% voting no.
There was also strong support for the deal within Fianna Fáil, with 74% of their members voting in favour of the deal.
Speaking after his party's vote, Micheál Martin said it was an important day for his party.
He said he didn't "understate the gravity of the situation" facing the country.
However, he noted: "I think it's a moment of opportunity, and a moment of hope for our people - that we face up to the challenges, overcome them, and lead to a better type of society."