Lester S. Hill (1891–1961) was an American mathematician and educator who was interested in applications of mathematics to communications.

He received a bachelor's degree (1911) and a master's degree (1913) from Columbia College and a Ph.D. from Yale University (1926).

Among his notable contributions was the Hill cipher.

He also developed methods for detecting errors in telegraphed code numbers and wrote two books.

This article about an American mathematician is a stub.