The Green Monster is the left field wall at Fenway Park in Boston, Massachusetts.
Green Monster may also refer to:
- Boston Red Sox
- Wally the Green Monster, mascot
- Green Monster (novel), featuring the Red Sox
- Infrastructure nicknames
- Hart Bridge in Jacksonville, Florida
- Central Artery, an elevated section of I-93 freeway in downtown Boston, Massachusetts, before it was rebuilt underground as part of the Big Dig project
- Other
- Green Monster (automobile), series of dragsters and land speed record cars built by Art Arfons between 1952 and 1991.
- Green Monster (EP), 2008 release by Suicide Silence
- Green Monster Games, later 38 Studios, now defunct, video game developers
- Green Monster of Braxton County, or Flatwoods monster, 1952 cryptid