Tarkus is the second studio album by English progressive rock band Emerson, Lake & Palmer, released on 4 June 1971 on Island Records. Following their debut tour across Europe during the second half of 1970, the group paused touring commitments in January 1971 to record a new album at Advision Studios in London. Greg Lake produced the album with Eddy Offord as engineer.

Side one features the 20-minute conceptual title track written by keyboardist Keith Emerson, the opening of which created friction between Lake and Emerson that almost split the group, but Lake agreed to pursue it and contributed musical ideas for it and wrote the lyrics. Side two features a collection of unrelated tracks of different styles. The artwork was designed by William Neal.

Tarkus went to number one on the UK Albums Chart, becoming the only album by the band to do so. It was a top 10 album worldwide, including the US, where it peaked at number 9. The album reached gold certification in the UK and US, the latter for 500,000 copies sold. It has been reissued and remastered several times, including a new stereo and 5.1 surround sound edition by Steven Wilson, with bonus and previously unreleased tracks from the original sessions, released in 2012.