Hans Lewy (20 October 1904 – 23 August 1988) was an American mathematician, known for his work on partial differential equations and on the theory of functions of several complex variables.

[5] At Göttingen, he studied both mathematics and physics; his teachers there included Max Born, Richard Courant, James Franck, David Hilbert, Edmund Landau, Emmy Noether, and Alexander Ostrowski.

He revisited Italy and France, but then at the invitation of the Emergency Committee in Aid of Displaced Foreign Scholars and with the assistance of Hadamard found a two-year position in America at Brown University.

[4][5] During World War II, Lewy obtained a pilot's license, but then worked at the Aberdeen Proving Ground.

In 1957, his famous example of a second-order linear partial differential equation was so stunning and unexpected that the whole field steered in a new direction, as well as shaping modern analysis in a significant way.