Panopea is a genus of large marine bivalve molluscs or clams in the family Hiatellidae. There are 10 described species in Panopea. Many of them are known by the common name geoduck, from the name of the Pacific geoduck in the Lushootseed language; .
Extinct species within this genus include:
The fossil record of the genus dates back to the Cretaceous (and maybe the Triassic) (age range: 242.0 to 0.012 million years ago). These fossils have been found all over the world.