Willem Kes (16 February 1856 in Dordrecht - 22 February 1934 in Munich) was a Dutch conductor. He was the first conductor of the Concertgebouw Orchestra (now called the Royal Concertgebouw Orchestra).
Kes learned the violin, studying with the famous Joseph Joachim in Berlin. From 1876 he started his career as a conductor. When the Concertgebouw Orchestra was started in Amsterdam in 1888 Kes was its conductor. He made it into a good orchestra. He had this job until 1895 when Willem Mengelberg took over. Kes went to Glasgow to conduct the Scottish Orchestra. In 1898 he took a conducting job in Moscow. From 1905 to 1926, Kes was director of a music conservatory (college) in Koblenz. He also worked in Dresden.
- Encyclopedie van de Muziek, pub Elsevier, Amsterdam, 1957.