The Tønder Festival was started in 1974 and is held every year for the last weekend in August. The festival has since developed into one of the most important European festivals in traditional and modern folk music. There are over 2000 volunteers attached to the festival.
The music program is composed of international artists from especially Ireland, Scotland, Canada, the United States, England and Scandinavia. The genres range from Irish and Scottish folk music to folk rock, blues and jazz, from songwriters to country, to modern Danish, Nordic, Baltic folk music and shows.
During the festival, the whole of Tønder is characterized by music and the city's population doubles.