Ernst Steinitz (13 June 1871 – 29 September 1928) was a German mathematician.

Steinitz was born in Laurahütte (Siemianowice Śląskie), Silesia, Germany (now in Poland), the son of Sigismund Steinitz, a Jewish coal merchant, and his wife Auguste Cohen; he had two brothers.

Subsequently, he took positions at Charlottenburg (now Technische Universität Berlin), Breslau, and the University of Kiel, Germany, where he died in 1928.

His thesis also contains the proof of Kőnig's theorem for regular bipartite graphs, phrased in the language of configurations.

Bourbaki[2] called this article "a basic paper which may be considered as having given rise to the current conception of Algebra".