Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings. The Atlantic salmon and trout of genus Salmo give the family and order their names.

Salmonids have a relatively primitive appearance among the teleost fish, with the pelvic fins being placed far back, and an adipose fin towards the rear of the back. They are slender fish, with rounded scales and a forked tail. Their mouths contain a single row of sharp teeth. Although the smallest species is just 13 centimetres (5.1 in) long as an adult, most are much larger, and the largest can reach 2 metres (6.6 ft).

All salmonids spawn in fresh water, but in many cases, the fish spend most of their life at sea, returning to the rivers only to reproduce. This type of life cycle is described as anadromous. They are predators, feeding on small crustaceans, aquatic insects, and smaller fish.