Otto Schönthal (1878 Vienna – 1961 Vienna) was a successful Viennese architect and designer, whose father, Leopold Schönthal, was also an architect. He studied at the Staatsgewerbeschule (State Trade School) in Vienna and then at the Wagnerschule (Wagner School)—so called because students in this program were under the guidance of architect Otto Wagner—at the Akademie der bildenden Künste (Academy of Fine Art). He won the Prix de Rome in 1901 and, right after finishing his studies, was already recognized for his Villa Vojcsik in Vienna (1901-1902). From 1902-1909, Schönthal was an assistant in Wagner’s studio, where he worked on major projects such as the Post Office Savings Bank and the Steinhof Church. He also worked on independent projects during this time.

In 1909, Schönthal became the editor of the influential review Der Architekt (The Architect), which had a close connection to the Wagnerschule. He also began an architecture and design practice with Emil Hoppe, later joined by Marcel Kammerer—all three were outstanding students at the Wagnerschule and colleagues from Wagner’s studio. The firm, combining the use of new materials and techniques with an awareness of traditional Viennese architecture, played an important role in the development of Viennese modernism in the years before World War I. These were the glory years for Viennese architecture, and the practice flourished. Among notable projects was the interior design of the Austrian pavilion at the "Esposizione Internazionale d’Arte" in Rome (1911) and the apartment building at Wiedner Hauptstrasse 126-128 in Vienna (1912-1913). The firm’s work, however, was interrupted by the war. During the austere post-war years, Hoppe and Schönthal continued to work together, most significantly on Vienna's social housing program in the 1920s and 1930s.

With the Nazi annexation of Austria in 1938, the practice closed. Schönthal, whose wife was Jewish, and his family left Austria for Switzerland and then Yugoslavia, only returning to Vienna after the end of World War II. Schönthal continued to work as an architect upon his return, especially on new apartment buildings for the city.