The winning ticket from last nights 30.9 million euro – Euromillions jackpot was sold in Co. Clare.
The National Lottery says the winner has yet to make contact and is urging people to check their tickets.
The winning numbers were 13, 18, 38, 42 and 45 – and the lucky stars were 7 and 11.
The Euromillions was last won in Ireland in 2020, when an anonymous winner claimed 49.5 million euro.
National Lottery Spokesperson Sarah Orr says the lucky winner needs to sign the back of the ticket, keep it in a safe place and make contact as soon as possible.