Karl Otto Clemens Wittgenstein (April 8, 1847 – January 20, 1913) was a German-born Austrian steel tycoon of Jewish origin.
A friend of Andrew Carnegie, with whom he was often compared, at the end of the 19th century he controlled an effective monopoly on steel and iron resources within the Austro-Hungarian Empire, and had by the 1890s acquired one of the largest fortunes in the world.
He was also the father of concert pianist Paul Wittgenstein, philosopher Ludwig Wittgenstein and of philanthropist Margaret Stonborough-Wittgenstein.