Willem Jeths studied composition under Hans Kox and Tristan Keuris in Utrecht, completing his studies there with the Composition Prize in 1988. He gained his doctorate in musicology in Amsterdam in 1991.

Jeths’ Novellette for violin and piano was selected for the ISCM World Music Days in Oslo in 1990, whilst Arcate, his first string quartet, received honourable mention in the Carl Maria von Weber-Wettbewerb in Dresden the following year. Glenz (1993), his first violin concerto, and his first piano concerto were awarded the second and third prizes at the Wiener Internationaler Kompositionswettbewerb in 1996. The Willem Jeths Festival held in Rotterdam in May 2000 was the first of a series of retrospectives of Jeths’ works. He was composer- in-residence with the Gelders Orkest and the Brabants Orkest during the 2004- 2005 season; these orchestras gave the premieres of his orchestral work Seanchai and the clarinet concerto Yellow Darkness. He composed his flugelhorn concerto Al fondo per l’oscuro for the Royal Concertgebouw Orchestra in 2002; their recording of the work was released in 2003. His second commission from the orchestra, a homage to Mahler entitled Scale, was first performed in December 2010. Jeths was composer-in-residence at the Doelen in Rotterdam during the 20o5-2006 season, where the Schönberg Ensemble gave the premiere of Meme, his double concerto for two violas and instrumental ensemble; he later reworked this piece for chamber orchestra at the request of the ZaterdagMatinee. The Muziekkwartier in Enschede in the Netherlands opened with Jeths’ first opera Hôtel de Pékin - Dreams for a dragon queen in 2008 and Jeths composed his second violin concerto Dyptich Portrait for the ZaterdagMatinee 2009-2010 season. Jeths’ music is now performed throughout the world. He has taught composition at the Conservatory of Amsterdam since 2006.