The Viljandi Folk Music Festival is a music festival in Estonia with a central focus on European folk music. It is traditionally held during the last weekend of July, when the otherwise quiet city of Viljandi is completely transformed as the small city center is suddenly flooded with people. The main attraction of the festival is the friendly atmosphere. Over 25,000 people attend the concerts every year, but many more just come to take part in the festivities. As such, it is the largest annual music festival in Estonia, and one of the largest folk music festivals in Europe.
The festival itself has grown from a more traditional Estonian folklore festival to a massive enterprise with an increasing number of international celebrities. Even some of the key native bands headlining the festival could easily be classified as folk rock (Vägilased) and even folk metal (Oort). The modern and popular music influences makes it highly appealing to the youth and almost all university students have been to the festival before they graduate, but hardcore fans of Estonian ethnic music prefer the more traditional festival held in Võru (south Estonia).