Tetraodontidae is a family of marine and freshwater fish in the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowers, blowies, bubblefish, globefish, swellfish, toadfish, toadies, botetes, toadle, honey toads, sugar toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines (unlike the thinner, hidden spines of the Tetraodontidae, which are only visible when the fish have puffed up). The family name comes from Ancient Greek τετρα- (tetra-), meaning "four", and ὀδούς (odoús), meaning "tooth", referring to the four teeth of the type genus Tetraodon.

The majority of pufferfish species are toxic, with some among the most poisonous vertebrates in the world. In certain species, the internal organs, such as the liver, and sometimes the skin, contain mucus tetrodotoxin, and are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan (as 河豚, fugu), Korea (as 복, bok, or 복어, bogeo), and China (as 河豚, hétún) when prepared by specially trained chefs who know which part is safe to eat and in what quantity. Other pufferfish species with nontoxic flesh, such as the northern puffer, Sphoeroides maculatus, of the Chesapeake Bay, are considered a delicacy elsewhere.

The species Torquigener albomaculosus was described by David Attenborough as "the greatest artist of the animal kingdom" due to the males' unique habit of wooing females by creating nests in sand composed of complex geometric designs.

The Tetraodontidae contains 193 to 206 species of puffers in 27 or 28 genera:

The following fossil genera are known:

Pufferfish are typically small to medium in size, although a few species such as the Mbu pufferfish can reach lengths greater than 50 cm (20 in).

Tetraodontiformes, or pufferfish, are most significantly characterized by their four beak-like teeth – hence the name combining the Greek terms "tetra" for four and "odous" for tooth. Each of the top and bottom arches is fused together with a visible midsagittal demarcation, which are used to break apart and consume small crustaceans. The lack of ribs, a pelvis, and pelvic fins are also unique to pufferfish. The notably missing bone and fin features are due to the pufferfish' specialized defense mechanism, expanding by sucking in water through an oral cavity.

Pufferfish can also have many varied structures of caltrop-like dermal spines, which account for the replacement of typical fish scales, and can range in coverage extent from the entire body, to leaving the frontal surface empty. Tetraodontidae typically have smaller spines than the sister family Diodontidae, with some spines not being visible until inflation.