Theodor van Eupen (24 April 1907 – 11 December 1944) was a member of the SS of Nazi Germany. A Holocaust perpetrator, he served as the commandant of the Treblinka I forced-labour camp (Arbeitslager) in occupied Poland during its entire course of operation. Unlike the parallel Treblinka extermination camp (Treblinka II) subordinate to the Operation Reinhard authorities in Berlin, Treblinka I was controlled by the SS and Police Leader in Warsaw. The labour camp was liquidated on 23 July 1944, ahead of the Soviet advance. By then, more than half of its cumulative number of some 20,000 inmates had died from summary executions, hunger, disease and mistreatment. The regular workforce consisted of 1,000–2,000 prisoners, terrorized by staff of about a dozen SS-men and 100 Wachmänner guards.