Operetta (German: Operette) is a 1940 musical film directed by Willi Forst and starring Forst, Maria Holst and Dora Komar. The film was made by Wien-Film, a Vienna-based company set up after Austria had been incorporated into Greater Germany following the 1938 Anschluss. It is the first film in director Willi Forst's "Viennese Trilogy" followed by Vienna Blood (1942) and Viennese Girls (1945). The film portrays the life of Franz Jauner (1832–1900), a leading musical figure in the city. It is both an operetta film and a Wiener Film.

When the schoolgirl Kate defends her friend, she is expelled from school. To conceal the incident from her parents, she positions herself ill. Promptly she falls in love with the treating doctor who cures her sudden illness not only, but marries his patient also immediately. But Kate soon bores the life of a doctor's wife. So she decides to secretly catch her ​​high school.