"Baba O'Riley" is a song by the English rock band The Who, written by guitarist and primary songwriter Pete Townshend. It is the opening track to the Who's fifth album, Who's Next (1971). In Europe, it was released as a single in October 1971, coupled with "My Wife". Performances of "Baba O'Riley" appear on several Who live albums.

The Who are an English rock band formed in London in 1964. Their classic lineup (1964–1978) consisted of lead vocalist Roger Daltrey, guitarist Pete Townshend, bassist John Entwistle and drummer Keith Moon. They are considered one of the most influential rock bands of the 20th century. Their contributions to rock music include the development of the Marshall stack, large public address systems, the use of synthesisers, Entwistle's and Moon's influential playing styles, Townshend's feedback and power chord guitar technique, and the development of the rock opera. They are cited as an influence by many hard rock, punk, power pop and mod bands. The Who were inducted into the Rock and Roll Hall of Fame in 1990.