The Norwegian Constitution Day is the National Day of Norway and is an official national holiday each year on May 17.

Among Norwegians, the day is referred to simply as "syttende mai" (meaning May Seventeenth), Nasjonaldagen (National Day) or less commonly, Grunnlovsdagen (Constitution Day). This public holiday marks the day in 1814 when Norway adopted its constitution.

Norway's Constitution which declared the country as a kingdom independent of Sweden after the Napoleonic Wars was signed at Eidsvoll on 17 May 1814. The constitution was based on American and French models, and elected the Crown Prince of Denmark and Norway, Christian Frederick, as king. While full independence was not achieved until 7 June 1905, 17th May remains Norway's National Day. The Norwegian parliament, held the first 17th of May celebration in 1836, and since then on the 17th of May has been regarded as the national day.

The 17th of May celebrations vary across Norway, but they all follow a traditional pattern that makes this a day centered on children. The highlights are the children’s processions, made up of school classes marching through the local community, led by the school band. Most children have their own small Norwegian flag to wave, and the route is lined with enthusiastic onlookers. In addition to flags, people typically wear red, white and blue ribbons. Although a long-standing tradition, it has lately become more popular for men, women and children to wear traditional outfits, called bunad. The children also make a lot of noise shouting "Hurra!", singing, blowing whistles and shaking rattles. After the procession there are games, entertainments and film shows, and plenty of hot dogs and ice cream. The first children’s processions were arranged in 1870. Since 1906, the Royal Family have gathered on the balcony of the Royal Palace in Oslo to wave to the children marching by.