A Quahog is one of a variety of hard-shelled clams. The Quahog is the state shellfish of Rhode Island. In Rhode Island, the word Quahog is alternately pronounced either "kwa-hog" or "co-hog".

The Quahog takes its name from the Narragansett Indian word "poquauhock", and in earlier times, the Narragansetts used to make beads called wampum from the shells of the Quahog. Indeed, the scientific name of the Quahog, Mercenaria mercenaria is related to the Latin word for "Money" for this very reason.

Quahogs are a popular food in Rhode Island, taking on different names based on its size. The term for different sized quahogs, from smallest to largest are "little necks", "cherry stones", and "quahogs". Quahogs are commonly eaten raw on the half-shell, sometimes with lemon and pepper sauce . Sometimes, quahogs are steamed, though they are not to be confused with their soft-shelled cousin, the steamer clam .

Quahogs are salt-water mollusks that thrive in salt concentrations of 18-26ppt, which is less salty than open ocean salinity of 35 ppt, and thus thrive in less-salty estuaries like Rhode Island's Narragansett Bay.

Although quahogs can be found along the East coast between Maine and Florida, they are particularly abundant between Cape Cod and New Jersey. Rhode Island, situated right in the middle of "quahog country", has supplied a quarter of the nation's total annual commercial quahog catch.

The Quahog was popularized by the animated television show Family Guy, which takes place in the town of Quahog, Rhode Island, which was named after the legendary Quahog clam.