Joseph Bernstein (sometimes spelled I. N. Bernshtein or Iosif Naumovič Bernštejn; Hebrew: יוס(י)ף נאומוביץ ברנשטיין; Russian: Иосиф Наумович Бернштейн; born April 18, 1945) is an Israeli mathematician working at Tel Aviv University. He works in algebraic geometry, representation theory, and number theory.