Siegfried Graetschus (9 June 1916 — 14 October 1943) was a German SS-Oberscharführer (Staff Sergeant) at Sobibor extermination camp in World War II during the deadliest phase of the Holocaust in occupied Poland. He was promoted to the rank of Untersturmfuhrer (Junior Storm Leader) during his time at Sobibor. Graetschus was a Nazi perpetrator of the genocide of the Jews in the implementation of Operation Reinhard. He was assassinated by a Sonderkommando prisoner during the Sobibor uprising.