Seafood is any sea animal that is served as food or is suitable for eating, particularly seawater animals, such as fish and shellfish including mollusks and crustaceans, bony and cartilaginous fishes, edible jellyfish, sea turtles, frogs, sea urchins, and sea cucumbers. The roe, or eggs, of some species are eaten as caviar. After cereals, seafood may be mankind's most important food, furnishing about 15% of the world's protein intake. Lean fish is equivalent to beef or poultry in its protein yield (18 – 25% by weight), but it is much lower in calories. Much seafood is eaten uncooked, either raw, dried, smoked, salted, pickled, or fermented. Otherwise it is cooked whole or cut into steaks, filets, or chunks. It is often used in stews or soups.

Edible seaweeds are rarely considered seafood, even though they come from seawater and are widely eaten around the world. The harvesting of seafood is known as fishing and the cultivation of seafood is known as aquaculture, mariculture, or simply fish farming.