Grendel is a monster in the Anglo-Saxon epic poem Beowulf, feared by all save Beowulf himself.
Grendel is a descendant of the biblical Cain, the first murderer. In Beowulf, Grendel haunts Heorot, the mead-hall of the Danes, and eats men too drunk to defend themselves. Beowulf leaves Geatland to defeat the monster bare-handed.
- Kennings for Grendel in the poem include "powerful monster", "herdsman of evil" and "guardian of crime".
- In the strange sci-fi update movie of 1999 starring Christopher Lambert, Grendel is played by Vincent Hammond as a bizarre blue blur.
- John C. Gardner's Grendel is Beowulf story from Grendel's point of view.
- Marillion have an early epic song named Grendel, which, according to then-singer Fish, was influenced by Gardner's book.
- Larry Niven and Steven Barnes' novel The Legacy of Heorot is, to an extent, a retelling of the poem, on an extraterrestrial world.