鳟（学名：Salmo trutta）又名褐鳟，为辐鳍鱼纲鲑形目鲑科鳟属的一种。

本鱼广泛分布于欧洲，并被引进到世界其他地区。

The brown trout (Salmo trutta) is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes both purely freshwater populations, referred to Salmo trutta morpha fario and S. trutta morpha lacustris, and anadromous forms known as the sea trout, S. trutta morpha trutta. The latter migrates to the oceans for much of its life and returns to fresh water only to spawn. Sea trout in the UK and Ireland have many regional names, including sewin (Wales), finnock (Scotland), peal (West Country), mort (North West England), and white trout (Ireland).