Folk songs are traditional tunes handed down orally from generation to generation. Some are as much as five or more centuries old. Usually the original composer is unknown, and the music may have changed substantially in the course of time. Most have only been written down comparatively recently, especially by late 19th century composers who published collections of folk songs from their own countries. The folk-song tended to become a symbol of nationalism in many countries, in the later 19th and early 20th centuries, although this trend was resisted in England.

Many types of music are included in folk songs., for example, lullabies, nursery rhymes, love songs, battle songs, ballads about historical events, and work songs. They all posses memorable and direct melodies, simple harmonies, and un-sophisticated words. They are usually strophic in form, that is they consist of many verses set to the same tune, sometimes with a 'chorus' interposed between each verse.

In Britain, Cecil Sharp and Vaughn-Williams were pre-eminent in writing down and publishing English folk-songs. The Scottish, Welsh and Irish songs are generally better-known then the English ones. In many continental European countries, the folk songs and associated folk-dances have formed the basis of a modern tourist industry, in which large-scale theatrical performances in brightly-coloured traditional costumes, are attended by eager bus-loads of tourists. In Austria and Switzerland, some folk songs originate from mountain farmers who 'yodelled' to send their voice over long distances. In Russia, folk song is often associated with folk dances such as the Trepak of the Cossaks. In Spain, flamenco guitarists accompany singers and dancers with their fiery and unique style.

The United States of America has inherited many folk traditions from the immigrants who settled there from all over the world. In particular, the spirituals or religious songs sung by the descendents of the African slaves, have been adopted as a feature of typical 'North American' music. In the 1960s some US songwriters started writing songs in a style blending folk elements with 'Pop' and 'Rock', and they called themselves 'folk-singers'. So in the USA the distinction between traditional folk songs, and modern rock, has become somewhat blurred.