The Theater in der Leopoldstadt (also: Leopoldstädter Theater) was an opera house in the Leopoldstadt district of Vienna, founded in 1781 by Karl von Marinelli, following the "Schauspielfreiheit" (ending of the court's monopoly on entertainment) by Joseph II in 1776. The 19th-century summer stage called the Thaliatheater was also managed by the Leopoldstadt.
In its early years, the theatre staged Singspiele and Possen mit Gesang, notably by the theatre's Kapellmeister Wenzel Müller and his assistant Ferdinand Kauer. The dramatist Ferdinand Raimund worked with the theatre in the 1820s.
The theatre was eventually demolished and rebuilt in 1847, under the name of the Carltheater.