Ernst Reijseger (born 1954) is an improvising cellist who started playing at 8, went on to study classical music with Anner Bylsma before turning to jazz and other improvised music in the 1970s. He played/recorded with: Sean Bergin, Martin van Duynhoven, Derek Bailey, Alan Purves, Franky Douglas, and Yo Yo Ma. He was member of the Theo Loevendie Consort, the Guus Janssen Septet, the Arcado Stringtrio, with Michael Moore and Han Bennink in Trio Clusone, Misha Mengelberg's Instant Composers Pool, the Gerry Hemingway quintet, and the Amsterdam String Trio. In 1985 he received the Boy Edgar prize and in 1995 the Bird Award (during the North Sea Jazz Festival).

Ernst Reijseger playes duo with Franco d'Andrea (piano), Louis Sclavis (clarinet, saxophone), Stian Carstensen (accordeon, banjo, guitar, mandoline, kaval); duo with Senegalese singer Mola Sylla, and trio with Eric Vloeimans (trumpet) and Anton Goudsmit (guitar); and regulary does concerts with Alan Purves in duo or in combination with traditional singers from Sardinia, the Tenores e Concordu de Orosei.

Ernst Reijseger writes music for film and documentaries. His written music is performed by well-respected cellist Larissa Groeneveld and pianist Frank Van de Laar with Reijseger as third 'free agent'. He also often plays solo concerts.