Carl George Niemann (July 6, 1908 – April 29, 1964) was an American biochemist who worked extensively on the chemistry and structure of proteins, publishing over 260 research papers. He is known, with Max Bergmann, for proposing the that proteins consist of 288 residue polypeptides or multiples thereof with periodic sequences of amino acids, and for contributing to the downfall of the cyclol model of protein structure.