Otto Lohse (September 21, 1859-May 5, 1925) was a German conductor and composer.
Born in Dresden, Lohse studied with Hans Richter and Felix Draeseke at the Dresden Conservatory. In 1882 he became conductor of two music societies in Riga, the Wagner Society and the Imperial Russian Music Society; seven year's later he became the first kapellmeister of the city's Stadttheater. In 1893 he became director of the Hamburg Stadttheater; while in Hamburg he married singer Katharina Klafsky. The couple traveled to the United States in 1896 to join the Damrosch Opera Company, returning to Germany a year later. From then on, Lohse held important conductorial posts at Strassburg (1897-1904), Riga Stadttheater (1899-1900), Cologne (1903-11), the Théâtre de la Monnaie (1911-12), and the Stadttheater in Leipzig (1912-23). He also directed performances of Richard Wagner's music dramas at Covent Garden, London, from 1901 until 1904. Lohse received the honorary title of Royal Professor in 1916. His only opera, Der Prinz wider Willen, was performed in Riga in 1890.
Lohse died in Baden-Baden in 1925.