The giant honeycomb oyster (Hyotissa hyotis) is a very large saltwater oyster, a marine bivalve mollusk.

Species in this family are known as honeycomb oysters or "foam oysters" because under magnification, their shell structure is foam-like.

Like most bivalves, the giant honeycomb oyster is a filter feeder.

Its native range is in deeper water in the Indo-Pacific Ocean.

It has however also been found recently as an accidentally introduced species in the Florida Keys.