Ernst Königsgarten, also known as Arnošt Königsgarten (14 July 1880 – 15 January 1942) was an Austrian businessman and fencer. He was the youngest member of the Austrian team in the Olympic 1906 Intercalated Games in Athens in four competitions, finishing sixth with the sabre. In 1907, he was one of the co-founders of the Wiener Fechtklub (Vienna Fencing Club), trained in the fencing academy of Luigi Della Santa and sat on the board of the Austrian Fencing Association and the Wiener AC. He fled Vienna after the Anschluss and returned to his hometown of Brno, but was deported by the Nazis and died in Theresienstadt.