This article explores the popular and critical reception of operetta in Russia during its European heyday, which broadly coincided with the transformative reign of Tsar Alexander II (1855-1881). It argues that the genre consistently drew audiences from most social strata and should not be considered, as some historians have suggested, a uniquely 'bourgeois' form of entertainment closely associated with the rise of the middle classes. It also argues that operetta crystallized a range of wider concerns about Russian culture and politics during the era of the Great Reforms. Many critics attacked operetta's frivolity and eroticism (held to be inconsistent with the aims of art), while radicals and conservatives regarded it as symptomatic of a new climate of political uncertainty (the former with hope, the latter with trepidation). The critical responses to operetta thus testified to its popularity and to the rapidity of change in Russia during the 1860s and 1870s.