The 8-track tape (formally Stereo 8; commonly known as the eight-track cartridge, eight-track tape, or simply eight-track) is a magnetic tape sound-recording technology that was popular in the United States from 1964 to 1988, when the Compact Cassette format took over. The format is regarded as an obsolete technology, and was relatively unknown outside the United States, the United Kingdom, Canada, New Zealand, Australia, Germany and Japan.

Stereo 8 was created in 1964 by a consortium led by Bill Lear of Lear Jet Corporation, along with Ampex, Ford Motor Company, General Motors, Motorola, and RCA Victor Records (RCA – Radio Corporation of America). It was a further development of the similar Stereo-Pak four-track cartridge introduced by Earl “Madman” Muntz (marketing and television set dealer), which was adapted by Muntz from the Fidelipac cartridge developed by George Eash. A later quadraphonic (four-channel sound as opposed to earlier more widely used stereo/two channel sound) version of the format was announced by RCA in April 1970 and first known as Quad-8, then later changed to just Q8.