Willy Hess (14 July 1859 – 17 February 1939) was a German violinist and violin teacher.
From 1904 to 1910, he was the concertmaster of the Boston Symphony Orchestra and taught violin at Harvard University. He also spent time as the leader of the Hallé Orchestra of Manchester, and as concertmaster in Frankfurt and Rotterdam. He then relocated to Berlin in 1910 to take the position of premier violin instructor at the Royal Academy of Music in Berlin, Germany (Berlin Hochschule fuer Musik, now a part of the Berlin University of the Arts). The composer Max Bruch, a friend of Hess, helped arrange Hess's appointment as professor. During the time of the Weimar Republic the Hochschule was the hub of the international music scene, and Hess was associated with many of the musical luminaries of his day and taught students who came to Berlin from all over the world, the most distinguished of whom was his fellow German Adolf Busch.
Hess taught a German style of right hand technique which emphasized wrist motion with very little finger motion.
He had no difficulty alternating between the violin and viola, and performed the viola part in the first performance of Bruch's Double Concerto for Clarinet, Viola and Orchestra, Op. 88, as well as the first performance of the Violin Concerto, op. 50 by Felix Woyrsch 1903 in Altona. It was also in 1910 that Bruch composed the Concert Piece for Violin and Orchestra, Op. 84, for Hess. Hess advised Bruch on composing for strings, and also performed the premieres of other works by Bruch.
Among works by other composers written for Hess was Arthur Foote's Ballade, Op. 69.
One of the instruments he played on was a Guadagnini.
Hess died in Berlin in 1939, aged 79.