"The Twelve Days of Christmas" is an English Christmas carol. A classic example of a cumulative song, the lyrics detail a series of increasingly numerous gifts given to the speaker by their "true love" on each of the twelve days of Christmas. The carol, whose words were first published in England in the late eighteenth century, has a Roud Folk Song Index number of 68. A large number of different melodies have been associated with the song, of which the best known is derived from a 1909 arrangement of a traditional folk melody by English composer Frederic Austin.

A cumulative song is a song with a simple verse structure modified by progressive addition so that each verse is longer than the verse before. Cumulative songs are popular for group singing, in part because they require relatively little memorization of lyrics, and because remembering the previous verse to concatenate it to form the current verse can become a kind of game.