Otto Weininger (; 3 April 1880 – 4 October 1903) was an Austrian philosopher who lived in the Austro-Hungarian Empire. In 1903, he published the book Geschlecht und Charakter (Sex and Character), which gained popularity after his suicide at the age of 23. Parts of his work were adapted for use by the Nazi regime (which at the same time denounced him). Weininger had a strong influence on Ludwig Wittgenstein, August Strindberg, Julius Evola, and, via his lesser-known work Über die letzten Dinge, on James Joyce.
