Otto Matthäus Zykan (29 April 1935, Vienna – 25 May 2006, Sachsendorf, Burgschleinitz-Kühnring) was an Austrian composer and pianist.
He also attended the Darmstadt summer courses (1958, 1964–1966), winning the Kranichstein Music Prize of the international piano competition on his first visit.
Gruber and Kurt Schwertsik, Zykan co-founded the Salonkonzerte Group and associated ensembles such as MOB art & tone ART (sometimes termed the 'Third Viennese School') to further his ideas about ‘instrumental theatre’, music that aimed for closer links between performance, music and language.
One of his earliest works was a piano concerto using serial techniques, which won a prize at the Innsbruck Youth Culture Week in 1963.
His three operas are Singers Nähmaschine ist die beste (1966, of which there is a revised film version, 1973), Kunst kommt von Gönnen (1980) and Auszählreim (1986).