Kleinmann is a common surname:
Dieter Kleinmann (born 1953), German politician
Georges Kleinmann, a French journalist
Larissa Kleinmann (born 1978), German cyclist
Louis Théodore Kleinmann (1907 - 1979)
Ralf Kleinmann (born 1971, Cologne, Germany), a German-American football player
Wilhelm Otto Max Kleinmann (1876 - 1945)
Kleinmann's Tortoise (Latin: Testudo kleinmanni, also Egyptian Tortoise, Leith's Tortoise)