Giant octopus is a common name for the genus Enteroctopus.

Giant octopus may also refer to:

Gigantic octopus, a cryptid St. Augustine Monster, a globster mistakenly believed to be a gigantic octopus Lusca, suggested to be a gigantic octopus Mega Shark Versus Giant Octopus, a low budget monster movie produced by The Asylum Oodako, a Toho kaiju that first appeared in King Kong vs. Godzilla (1962), also known as the Giant Octopus

See also Haliphron atlanticus, thought to be the second largest octopus species Kraken, Norse sea monster Cthulhu, Lovecraftian horror monster Vampire squid, a seemingly cephalopod related to squid and octopuses that feeds off marine snow