Opernhaus Dortmund is the opera house of Dortmund, Germany, operated by the Theater Dortmund organisation. A new opera house opened in 1966, replacing an earlier facility which opened in 1904 and was destroyed during World War II. It was built on the former site of the Old Synagogue, which was demolished by the Nazi local government in the 1930s.

Dortmund is the third-largest city in North Rhine-Westphalia, after Cologne and Düsseldorf, and the ninth-largest city in Germany. With a population of 612,065 inhabitants, it is the largest city of the Ruhr as well as the largest city of Westphalia. It lies on the Emscher and Ruhr rivers in the Rhine-Ruhr Metropolitan Region, the second biggest metropolitan region by GDP in the European Union, and is considered the administrative, commercial, and cultural centre of the eastern Ruhr. Dortmund is the second-largest city in the Low German dialect area, after Hamburg.