Corny Ostermann, born Cornelius Andreas Oostermann (born September 18, 1911 in Linden (now part of Hannover)—died during the Second World War; officially declared dead in 1949) was a German musician and jazz bandleader.
Osterman was active with a swing orchestra in Berlin in the late 1930s despite the Nazi government's ban on swing music.
Between 1938 and 1943 he recorded shellacs with his orchestra, some of them re-edited later.
As late as 1943, he was playing in the orchestra of Helmut Gardens.
After his conscription into Wehrmacht, he went missing and was officially declared dead in 1949.