Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising over 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than 10 cm (3.9 in) in length, and the family includes some of the smallest vertebrates in the world, such as Trimmatom nanus and Pandaka pygmaea. Trimmatom nanus are under 1 cm (3⁄8 in) long when fully grown, while the Pandaka pygmaea standard length is 9 mm (0.35 in), with a maximum known standard length of 11 mm (0.43 in). Some large gobies can reach over 30 cm (0.98 ft) in length, but that is exceptional. Generally, they are benthic or bottom-dwellers. Although few are important as food fish for humans, they are of great significance as prey species for other commercially important fish such as cod, haddock, sea bass and flatfish. Several gobiids are also of interest as aquarium fish, such as the dartfish of the genus Ptereleotris. Phylogenetic relationships of gobiids have been studied using molecular data.

Fossils of gobiids date back to the Early Oligocene.

The most distinctive aspects of gobiid morphology are the fused pelvic fins that form a disc-shaped sucker. This sucker is functionally analogous to the dorsal fin sucker possessed by the remoras or the pelvic fin sucker of the lumpsuckers, but is anatomically distinct; these similarities are the product of convergent evolution. The species in this family can often be seen using the sucker to adhere to rocks and corals, and in aquariums they will stick to glass walls of the tank, as well.

Gobiidae are spread all over the world in tropical and temperate near shore-marine, brackish, and freshwater environments. Their range extends from the Old World coral reefs to the seas of the New World, and includes the rivers and near-shore habitats of Europe and Asia. Gobies are generally bottom-dwellers. Although many live in burrows, a few species (e.g. in the genus Glossogobius) are true cavefish. On coral reefs, species of gobiids constitute 35% of the total number of fishes and 20% of the species diversity.

The family Gobiidae underwent a major revision in the 5th edition of Fishes of the World. Before the revision the Gobiidae contained six subfamilies: Gobiinae, Benthophilinae, Amblyopinae, Gobionellinae, Oxudercinae, and Sicydiinae. The revision retained the first two subfamilies and removed the other four to a separate family, the Oxudercidae. In addition, species formerly placed in the families Kraemeriidae, Microdesmidae, Ptereleotridae and Schindleriidae were added to the revised Gobiidae, although no subfamilies were described.

The two formerly recognised subfamilies where the species have been retained in Gobiidae in the 5th Edition of Fishes of the World:

Members of Benthophilinae are endemic to the Ponto-Caspian region (including the Marmara, Black, Azov, Caspian, and Aral Seas). The representatives of the subfamily have fused pelvic fins and elongated dorsal and anal fins. They are distinguished from the closely related subfamily Gobiinae by the absence of a swimbladder in adults and location of the uppermost rays of the pectoral fins within the fin membrane. Its members include tadpole gobies, monkey gobies, and bighead gobies.

Members of the Gobiinae are known as true gobies. It is the most widespread and most diverse of the subfamilies formerly recognised under the Gobiidae, containing around 2000 species and 150 genera.