Gertrude Rhinelander Waldo (May 12, 1842 – May 27, 1914) was an American heiress known for commissioning the Rhinelander Mansion located in Manhattan at 867 Madison Avenue on the south-east corner of 72nd Street, designed in the 1890s by Kimball & Thompson and completed in 1898. According to most sources, she never lived in the mansion, but chose to reside with her sister in a row house across the street from the mansion.