Saint Patrick's Day, also referred to as Saint Paddy's Day, commemorates one of the patron saints of Ireland, Saint Patrick. It is typically celebrated on March 17, though it can be moved by church authorities when it coincides with the Holy Week to avoid an overlap. It is the national holiday of Ireland, but it is also celebrated in other countries all over the world, such as Canada, the United States, the United Kingdom and Australia.

The Roman Catholic Church designated it as a holy day of obligation, where Roman Catholics generally attend mass, because of the efforts of the Franciscan scholar Luke Wadding in the 17th century. This holiday is commonly celebrated during the Lenten Season. The religious tradition of abstaining from meat during Fridays is sometimes revoked when Saint Patrick's Day is on a Friday.

This holiday is celebrated around Irish themes. The color green is commonly associated with this holiday, and celebrants typically wear green clothing to participate in the revelry. Another item closely tied to Irish culture is the shamrock, or a three leaf clover. It is widely believed to bring good luck to the bearer, though it is more appropriate for the four leaf clover, which is different from the shamrock altogether. An old Irish tale recollects how Saint Patrick used the three leafs of the clover to represent the Holy Trinity, the Father, the Son and the Holy Spirit.

There is an annual Saint Patrick's Day Parade in Dublin as part of a five day festival. Other cities in Ireland, such as Cork, Belfast, Limerick and Waterford, also hold their own parades and festivals. Aside from parades, drinking is also a common activity done to celebrate during Saint Patrick's Day. Traditional Irish alcoholic beverages are usually consumed in great amounts, at least more than the usual as drinking is a very common practice in Ireland. Some examples of these beverages are beer, stout and Irish whiskey. Some sectors in the religious community have lamented the fact that the holiday is typically regarded as one for drunken revelry instead for religious purposes.

The Irish government recently started a campaign to enhance the knowledge surrounding Irish culture through Saint Patrick's Day. They established the Saint Patrick's Day Festival to achieve the desired result. This festival lasts for a period of five days. The biggest celebrations are held in Dublin, though other parts of Ireland have their own celebrations. There are numerous parties and celebratory events, which are open to the public. Some examples include street theatre, carnivals and street performances. The best part is that they are mostly free of charge as they are all part of the celebration.

While the festivities are ongoing, it is commonplace to see people of all ages wearing green clothing and headgear. Shamrocks are also a very prominent sight. Tourists and residents alike have shamrock designs on their cheeks, as drawn by artists. Eating Irish food is also common as they pair it with their favorite drink, with corned beef and cabbage being prime examples.