"Halo of Flies" is a 1973 single by rock band Alice Cooper taken from their 1971 album Killer. The single was only released in the Netherlands, two years after the song appeared on the album. The song was, according to Cooper's liner notes in the compilation The Definitive Alice Cooper, an attempt by the band to prove that they could perform King Crimson-like progressive rock suites, and was supposedly about a spy organization.
Upon its 1973 single release, the song became a top 10 hit in the Netherlands and also charted in neighboring Belgium. The single release featured the B-side "Under My Wheels", also a song of the Killer album, which had already been released as a single two years prior.