Leon Lichtenstein (16 May 1878 – 21 August 1933) was a Polish-German mathematician, who made contributions to the areas of differential equations, conformal mapping, and potential theory.

Leon Lichtenstein was born on 16 May 1878 to an Ashkenazi Jewish family in Warsaw, then part of the Russian Empire.

He studied in Berlin, earning both a doctorate in mechanical and electrical engineering at the Technische Hochschule Berlin and a doctorate in mathematics at the Friedrich Wilhelm University with a thesis on differential equations written under the supervision of Hermann Schwarz and Friedrich Schottky.

From 1902 he worked as an electrical engineer for Siemens & Halske; then, from 1910, he turned to the academic world by becoming privatdozent at the Berlin Technische Hochschule.

In 1933, as the Nazi party came to power in Germany, Lichtenstein abandoned his position at the university and left to Poland, as he would have been dismissed anyway for being Jewish.