Jef Diederen (Heerlen, 25 August 1920-Amsterdam, 26 March 2009) was a Dutch painter and graphic artist. He studied at the Middelbare Kunstnijverheidsschool in Maastricht from 1939 to 1943. There he met the artists Pieter Defesche and Ger Lataster. In 1943 he enrolled in the Rijksacademie voor Beeldende Kunsten in Amsterdam and graduated in 1951. In this period he also got to know Karel Appel and Corneille. Until 1955 he painted landscapes of his native region Zuid-Limburg. Thereafter he began to develop an abstract style with bold colours. His work was especially inspired by France. Besides his paintings, he also created murals and window frames. He taught at the art academy in Den Bosch.