Siegfried Graetschus (9 June 1916 — 14 October 1943) was an SS-Oberscharführer (Staff Sergeant) at Sobibor extermination camp. In the process, Graetschus aided with the genocide of Jews and other peoples at Sobibor during Operation Reinhard of The Holocaust. Gratschus joined the SS in 1935 and the Nazi Party in 1936. He served at Bernburg Euthanasia Centre and Treblinka extermination camp before being posted to Sobibor in August 1943. He succeeded Erich Lachmann as commander of the approximately 200 Ukrainian guards at Sobibor.