The name giant rat has been applied to various species of large rats (or animals that appear similar to large rats) and may refer to:

Africa Gambian pouched rat, Cricetomys gambianus Giant pouched rat, genus Cricetomys Malagasy giant rat, Hypogeomys antimena

Asia and New Guinea Flores giant rat, Papagomys armandvillei Mountain giant Sunda rat, Sundamys infraluteus Giant cloud rats, southern giant slender-tailed cloud rat Phloeomys cumingi and northern Luzon giant cloud rat Phloeomys pallidus White-eared giant rats, western white-eared giant rat, Hyomys dammermani and eastern white-eared giant rat Hyomys goliath Woolly rats, genus Mallomys Large bamboo rat, Rhizomys sumatrensis

South America Coypu, nutria, or river rat,. Myocastor coypus Capybara, genus Hydrochoerus Woolly giant rat, Kunsia tomentosus

Extinct species East Timor giant rat, an extinct species, genus Coryphomys Tenerife giant rat, an extinct species, Canariomys bravoi Fossorial giant rat, Kunsia fronto

Fictional characters The Giant Rat of Sumatra, a giant rat featured in the Sherlock Holmes stories by Arthur Conan Doyle Kingdok, a primary antagonist in the Bone series of comics Giant Rats, a recurring enemy in the Dark Souls series

See also Gigantism, the phenomenon of animals to grow to giant sizes relative to their species Rat