The Grayling (Thymallus thymallus) is a species of freshwater fish belonging to the salmon family Salmonidae. It is native to the Palearctic ecozone (belonging or pertaining to a geographical division comprising Europe, Africa north of the tropic of Cancer, the northern part of the Arabian Peninsula, and Asia north of the Himalayas), and is widespread throughout northern Europe, from the United Kingdom and France to the Ural Mountains in Russia. It was introduced to Morocco in 1948, however it appears to have not become established there. The grayling prefers cold, clean, running river waters, but also occurs in lakes and, exceptionally, in brackish waters around the Baltic Sea.

The Grayling adult has a maximum recorded length of 24 inches, and a maximum weight of 15 pounds. This species has 5 to 8 dorsal and 3 to 4 anal spines, which are not present in other species. They also have a smaller number of soft rays in these fins. Graylings can live to an average age of 14 years.

The Grayling is omnivorous and feeds on vegetable matter as well as crustaceans, insects, spiders, mollusks, zooplankton, and other small fishes (mainly Eurasian minnows and yellow perch). They also prey for larger fish, including the Huchen. Though the grayling is a protected species in its native habitat, it is raised commercially for sport fishing.