Lev Genrikhovich Schnirelmann (Russian: Лев Ге́нрихович Шнирельма́н), alsoShnirelman, Shnirel'man (January 2, 1905 in Gomel – September 24, 1938 in Moscow) was a Soviet mathematician who sought to prove Goldbach's conjecture. In 1931, using the Brun sieve, he proved that any natural number greater than 1 can be written as the sum of not more than 20 prime numbers.

His other fundamental work is joint with Lazar Lyusternik. Together, they developed the Lyusternik-Schnirelmann category, as it is called now, based on the previous work by Henri Poincaré, David Birkhoff, and Marston Morse. The theory gives a global invariant of spaces, and has led to advances in differential geometry and topology.

Schnirelmann graduated from Moscow State University (1925) and then worked in Steklov Mathematical Institute (1934 – 1938). His advisor was Nikolai Luzin.

According to Pontryagin's memoir, Schnirelmann committed suicide in Moscow.