Theodor Lessing (8 February 1872, Hanover – 31 August 1933, Marienbad) was a German Jewish philosopher.
He is known for opposing the rise of Hindenburg as president of the Weimar Republic and for his classic on Jewish self-hatred (Der jüdische Selbsthaß), a book which he wrote in 1930, three years before Hitler came to power, in which he tried to explain the phenomenon of Jewish intellectuals who incited anti-Semitism against the Jewish people and who regarded Judaism as the source of evil in the world.
Lessing's political ideals, as well as his Zionism made him a very controversial person during the rise of Nazi Germany. He fled to Czechoslovakia where he lived in Marienbad in the village of a local social democratic politician. On the night of 30 August 1933, he was assassinated by Sudeten German Nazi sympathizers. Lessing was shot through a window of the villa where he lived. His assassins were Rudolf Max Eckert, Rudolf Zischka and Karl Hönl. They fled to Nazi Germany after the assassination.
Lessing's philosophical views were influenced by Nietzsche and African Spir. According to Theodore Ziolkowski in Lessing's Geschichte als Sinngebung des Sinnlosen (History as Giving Meaning to the Meaningless), "writing in the tradition of Nietzsche, argued that history, having no objective validity, amounts to a mythic construct imposed on an unknowable reality, in order to give its some semblance of meaning."