Alex Hargreaves is an American violinist from Corvallis, Oregon who performs and writes progressive acoustic music. Hargreaves was the youngest person ever to win the Grand Champion division at the National Oldtime Fiddlers' Contest in Weiser, Idaho at the age of 15.

Hargreaves is a member of Mike Marshall’s Big Trio and also performs regularly with Sarah Jarosz, appearing on both of her albums to date. His debut solo album, "Prelude", was released in 2010.