In 1982, English progressive rock band Marillion wrote and recorded a 17-minute progressive opus entitled "Grendel" that was based on the book. A version of the song shortened by a little under three minutes was released as a B-side to the single "Market Square Heroes" (now out of print). The song is currently available on the two-disc version of the Script for a Jester's Tear album.
Seattle, WA indie rock band Sunny Day Real Estate has a song called "Grendel" that was based on the book. The song appears on the album, Diary.
On June 8, 2006, an opera based on the novel was premiered at the Los Angeles Opera. The score was composed by Elliot Goldenthal, with a libretto by Julie Taymor and J.D. McClatchy. Ms. Taymor also directed the piece. The part of Grendel was sung by bass-baritone Eric Owens, the dragon by mezzo-soprano Denyce Graves, the Shaper by tenor Richard Croft, Wealtheow by soprano Laura Claycomb, and Unferth by tenor Jay Hunter Morris. Beowulf, a dancing role, was performed by Desmond Richardson. The opera was produced in New York City during the summer of 2006 at the New York State Theater as part of the Lincoln Center Festival.