October 23, 1941:
- The German government banned the emigration of Jews.
- The British destroyer HMS Cossack was torpedoed and damaged in the Atlantic Ocean by the German submarine U-563. The Cossack tried to return to Gibraltar for repairs but would sink in bad weather four days later.
- The first of the two Mesovouno massacres was carried out by the Wehrmacht in the Greek village of Mesovouno.
- German submarine U-593 was commissioned.