Otto Schack

Otto Schack may refer to:
 * Otto Didrik Schack, 1st Count of Schackenborg (1652–1683)
 * Otto Didrik Schack, 3rd Count of Schackenborg (1710–1741), grandson of the above
 * Otto Didrik Schack, 9th Count of Schackenborg (1882–1924), last Count of Schackenborg
 * Otto Wilhelm Christian Schack (1818–1875), Danish-born American broker