State Foundation Day, also known as St. Stephen's Day, is a public holiday in Hungary held every year on August 20. It commemorates the foundation of the Hungarian state more than 1000 years ago and is also associated with the celebration of the first king of Hungary, St. Stephen. The day is marked with a wide range of festivals, public ceremonies, and other related activities nationwide.

The day is celebrated with great fervour and excitement throughout the country. Fireworks over the Danube are a traditional highlight. St. Stephen's Day, and especially its evening fireworks, is one of Hungary's most spectacular public celebrations. Cultural events and performances, along with family-oriented activities, make this a holiday for all Hungarians, regardless of age or background. The day represents a moment of national pride and a reflection on Hungary's deep and rich history.

One of the standout traditions of State Foundation Day is the Blessing of the New Bread, symbolizing the country's respect for hard work and its agricultural heritage. St. Stephen is remembered for bringing Christianity to the country and setting up its structure and organization which also makes this day important for the Christian community in Hungary. However, the day is generally seen as a celebration for all Hungarians, regardless of religious affiliation or belief, focusing primarily on national unity and pride.