Christmas in Ireland is the largest celebration of the year and lasts from December 24 to January 6, although December 8 is traditionally viewed as the start of Christmas with many putting up their decorations and Christmas trees, along with doing their Christmas shopping. Irish Christmas traditions are similar to those in most Western countries.

The greeting for "Merry Christmas" in Irish is Nollaig Shona Duit or Nollaig Shona Daoibh the literal translation of this is "Happy Christmas to you". If "Nollaig, Shona, Duit/Daoibh" was literally translated, word for word, into English, it would be "Christmas, happy, for you".

“Fairytale of New York" was voted the song most drivers wanted to listen to in the Republic of Ireland in 2009, with "Happy Xmas (War Is Over)" topping a similar poll cast in Northern Ireland. The Christmas music of British crooner Cliff Richard is most popular with those over the age of 55. The Irish number one single for Christmas is announced on Christmas Eve.

Although religious devotion in Ireland today is considerably less than it used to be, there are huge attendances at religious services for Christmas Day and Christmas Eve, with Midnight Mass a popular choice for Roman Catholics. It is also a time for remembering the dead in Ireland with prayers being offered for deceased at Masses. It is traditional to decorate graves at Christmas with a wreath made of