Karl-Otto Saur (February 16, 1902 in Düsseldorf – July 28, 1966 in Pullach) was State Secretary in the Reich Ministry for armaments and war production in Germany during the Nazi era and de jure last defence minister of the Third Reich. Saur was an engineer by profession. After graduation, he joined Thyssen, then took over the running of the family engineering firm in Freiburg after the death of his father. This business went into bankruptcy in 1928 on the threshold of the Great Depression.