The winning ticket for last night's €30,928,078 EuroMillions jackpot was sold in Co Tipperary.
The numbers drawn were 13, 18, 38, 42 and 45 and the lucky stars were 7 and 11.
The National Lottery has urged people to check their tickets and advised the winner to sign the back of the ticket and keep it in a safe place.
It said that it will be revealing more details about the location of the winning ticket in the coming days.
A National Lottery spokesperson said: "The lucky winner should make contact with our prize claims team and we will make arrangements for the winner to claim their prize."
It is the latest in a long line of Irish jackpot wins since the game began in 2004.
Apart from Ireland, EuroMillions tickets can be bought in Austria, Belgium, Britain, France, Luxembourg, Portugal, Spain and Switzerland.
Meanwhile, the winning ticket for Wednesday's €4.6m Lotto jackpot was sold at the Centra store at Summerhill Court in Co Meath.
The win there came just over a month after the winning Millionaire Raffle ticket was sold at the same store.