Rhinelander Waldo (May 24, 1877 – August 13, 1927) was appointed the seventh New York City Fire Commissioner by Mayor William Jay Gaynor on January 13, 1910. He resigned on May 23, 1911, less than two months after the deadly Triangle Shirtwaist Factory fire to accept an appointment as the eighth New York City Police Commissioner. On December 31, 1913, he was dismissed by the outgoing acting mayor, Ardolph Kline. Among other achievements in office, Waldo contributed to the motorization of both departments.