Karl Fritzsch (10 July 1903 – 2 May 1945) was a German SS official who served as deputy and acting commandant at the Auschwitz concentration camp from 1940 to 1941.

Karl Fritzsch was born on 10 July 1903 in Nassengrub in the Kingdom of Bohemia in Austria-Hungary (present-day Mokřiny, Czech Republic) into a Bohemian German family.

He became a career SS man and acquired a position at the Dachau concentration camp in 1934, almost as soon as it opened, as a member of the 1st SS-Totenkopf Regiment "Upper Bavaria" .

Fritzsch quickly obtained a fearsome reputation in Auschwitz, selecting prisoners to die of starvation in reprisal for escape attempts.

Together with Höss, he was responsible for the torture death of victims locked inside standing cells in the basement of the Bunker, i.e. the Block 11, or 13 prison, until they died.

Lagerführer Karl Fritzsch referred to the corpses beneath the tree as 'a present' for the living, and forbade the singing of Polish Christmas carols."

While Höss was on an official trip in late August 1941, Fritzsch ordered the killing of Soviet prisoners of war by being locked in cells in the basement of the Bunker.

[1] It is commonly believed that Fritzsch was killed in action in the Battle for Berlin on 2 May 1945, a week before German surrender, but his final fate had long remained unknown.

In a separate report from 1966 by the Kriminalpolizei Regensburg, Fritzsch's wife states that she had no reason to doubt her husband's death and that she had received his wedding ring and personal letters.