Ostrea edulis, commonly known as the European flat oyster, is a species of oyster native to Europe. In Britain and Ireland, regional names include Colchester native oyster, mud oyster, or edible oyster.

Ostrea edulis is a bivalve mollusc that has an oval or pear shaped shell with a rough, scaly surface. The irregular shell has a distinct hooked beak, patterned with delicate foliation. The two halves (valves) of the shell are different shapes subcircular to circular and inequivalve.

Ostrea edulis is commonly known as the European Oyster. It is native to the Northeast Atlantic from Norway to Morocco, and the Mediterranean and Black Seas. This oyster has been cultivated in European waters since before Roman times. It has been introduced and is established on the East Coast of North America, Australia and South Africa.