Istanbul of the 1920s evoked a period of transition and redefinition in the aftermath of World War I and the onset of the Turkish Republic (1923). Precisely, what position Istanbul would occupy as well as its constituents in the nascent republic was in flux. Debates around distinctly modern, transnational cultural practices emerged in Istanbul's illustrated press, determining the parameters, albeit ambiguous, around modern life. One such debate centered upon jazz and its respective dances, namely the Charleston. Jazz represented a distinctively interwar, transnational sound. Cultural critics perceived the movement and rhythms as “uncontrollable” and difficult to describe. Critic Akil Cem had even proposed that the Charleston steps be “tamed” by limiting the steps from twenty to five, while writer Fikret Adil referred to jazz as “awakening a horrible monster.” The jazz public exuded a heterogeneous, cosmopolitan character that blurred public borders in terms of class hierarchies and gendered, linguistic, and ethnic boundaries, and threatened an emerging Turkish cultural order. Both the narratives of American jazz exceptionalism and a predominant 1930s-centric Turkish nationalist narrative marginalized if not rendered silent the 1920s Istanbul jazz scene. In this article, I historicize jazz and highlight a transnational border crossing of performers and cultural products. By so doing, I place the city as being a participant of an urban transnational latitude. Specifically, I look at how jazz was identified, criticized, and appropriated by engaging with various printed and visual materials. I argue that the “horrible monster” of jazz was the site of negotiating different notions of the public in 1920s Istanbul.