A piano roll is a music storage medium used to operate a player piano, piano player or reproducing piano. Piano rolls, like other music rolls, are continuous rolls of paper with holes punched into them. These perforations represent note control data. The roll moves over a reading system known as a tracker bar; the playing cycle for each musical note is triggered when a perforation crosses the bar.

A player piano, also known as a pianola, is a self-playing piano with a pneumatic or electro-mechanical mechanism that operates the piano action using perforated paper or metallic rolls. Modern versions use MIDI. The player piano gained popularity as mass-produced home pianos increased in the late 19th and early 20th centuries. Sales peaked in 1924 and subsequently declined with improvements in electrical phonograph recordings in the mid-1920s. The advent of electrical amplification in home music reproduction, brought by radios, contributed to a decline in popularity, and the stock market crash of 1929 virtually wiped out production.