Salmo is a genus of fish in the salmon family (Salmonidae) that includes the familiar species Atlantic salmon (Salmo salar) and brown trout (Salmo trutta). The natural distribution of the genus is chiefly European. Only the range of the Atlantic salmon extends to northern North America. The salmons and trouts of the Pacific basin belong to another genus, Onchorhynchus.
The number of distinct species and subspecies in Salmo is a debated issue. Atlantic salmon and brown trout are widespread species, but most of the other suggested taxa are narrowly distributed forms endemic to single watersheds.