G. grandis

G. grandis may refer to:
 * Gahnia grandis, a perennial plant species found in southeastern Australia and Tasmania
 * Geosaurus grandis, an extinct marine crocodyliform species that lived during the Late Jurassic to the Early Cretaceous
 * Gilbertsmithia grandis, an alga species in the genus Gilbertsmithia
 * Glechoma grandis, a flowering plant species in the genus Glechoma
 * Glirodon grandis, an extinct mammal species found in North America that lived during the Upper Jurassic