Easter Monday is a Christian holiday celebrated the next day after Easter Sunday. It is also called as Dyngus or Splash Monday, among many Polish communities where children often play water games.

The Lord has risen from the dead, as he foretold. "Let there be happiness and rejoicing for he is our King forever, alleluia". According to Moses and the prophets Christ was to suffer all "these things and so to enter into His glory".

One theory is that Dyngus originates from the baptism on Easter Monday of Mieszko I (Duke of the Polans) in 966 AD, uniting all of Poland under the banner of Christianity. Dyngus and Smigus were twin pagan gods, the former representing water and the moist earth (Dyngus from din gus - thin soup or dingen - nature), and the latter representing thunder and lightning (Smigus from smigac or to make a whooshing sound). In this theory, the water tradition is the transformation of the pagan water god into the Christian baptism. The custom of pouring water was an ancient spring rite of cleansing, purification, and fertility. Most recently, the tradition has changed to become fully water-focused, and the smigus part is almost forgotten.

Christian people would add fragrant oil or perfume to the water they brought home from church, and then use this water to sprinkle and bless their food, pets, gardens and homes.

On Monday morning, Christian men would wake their wives with a spritz of the perfumed water as they whispered, "May you never wither". On Easter Tuesday, women would return the favor as they awakened their husbands with a bucketful of the scented water!

The United States has its own tradition for Eastern Monday, known as the Egg Roll, which occurs at the White House. This tradition can be traced as far back as 1878, although it was not always held in the earlier years. The White House Easter egg collection involves a tradition that began in 1994 where each state sends a decorated egg to the White House for display. Artists from across the United States created decorated eggs, the following year's commemorative egg which is presented to the President and First Lady. The collection is coordinated by the American Egg Board. Easter egg races are held in other parts of the world, including Germany.

Easter Monday is a relaxed day for many Orthodox Christians. For some, it is a reflection of the events that occurred during Holy Week. Easter Monday is a day to finish leftover Easter meals that were not eaten the day before.

In France, on Easter Monday, the inhabitants make a huge omelet with 15,000 eggs in a pan four meters (about 13 feet) wide in diameter. They then hold a communal meal to eat it. There is a colorful parade on Easter Monday in the village of Cargese on the island of Corsica. Local guilds and the Greek Orthodox and Catholic churches take part. After the parade, the fields are blessed for the coming year.

In Poland and parts of the United States, it is called Dyngus Day. In the Eastern Orthodox Church and those Eastern Catholic Churches which follow the Byzantine Rite, Easter Monday is known as Bright or Renewal Monday, and is the second day of Bright Week.

Another related custom, unique to Poland is that of sprinkling bowls of ashes on people or houses, celebrated a few weeks earlier at the "polposcie". This custom is almost forgotten, but still practiced in the area around borders of Mazuria and Masovia.

In Egypt, the ancient festival of Sham El Nessim (literally means "smelling of the breeze") is celebrated on the Coptic or Easter Monday, though the festival dates back to Pharonic times (about 2700 BC). It is celebrated by both Egyptian Christians and Muslims as an Egyptian national holiday rather than as a religious one. Traditional activities include painting eggs, taking meals outdoors, and eating fermented mullet.

The world's largest organized Dyngus Day celebration occurs in Buffalo, New York. In Buffalo's eastern suburbs and the city's Historic Polonia District, Dyngus Day is celebrated with a high level of enthusiasm.

Although Dyngus Day was celebrated in traditional Polish neighborhoods of Buffalo dating back to the 1870s, modern Dyngus Day in Buffalo had its start with the Chopin Singing Society.