In 1909 the Istanbul police commissioner successfully lobbied the Dahiliye Nezareti to create a new police force for the imperial capital. The zabıta-yı ahlakiye (morality police) were tasked with the moral upkeep of the city and swiftly set about harassing the owners, patrons, and prostitutes of Istanbul’s umumhaneler. These sites of sex and vice were increasingly viewed by the state as a fifth column which undermined the empire’s strength from within and had to be countered. Two years later the experiment of the zabıta-yı ahlakiye was codified into an empire wide body called Asayiş Müfettiş-i Umumiliği; the General Inspector of Public Order. In this paper I argue that these inventions were an anxious response to the numerous external threats faced by the empire in its final decade. Those lawmakers, politicians, intellectuals, bureaucrats, and soldiers that clustered around the state hurriedly looked for any and all means of national strengthening to meet this threat. Urban space in general, and Istanbul in particular, became laboratories for a new kind of disciplinary power that aimed at creating a healthy national body, a national body that was unified, defended, and morally upstanding. At the same time, cities were sites where modernity was lived, where technology and social change were at their fastest, and where new alafranga behaviours were first adopted. Anxieties came from within and without. Prostitutes were labelled an existential threat to the empire while foppish, fashionable young men became emblematic of Ottoman impotency itself. Studies of late-Ottoman sexuality have tracked anxious attempts to hide homosexual behaviour seen as “illicit” and a sign of Ottoman decline by European observers. I build on these arguments to focus closely on this anxiety and how it manifested across a wide range of urban socio-sexual practices. I examine the documentary history of morality policing alongside literary sources that narrate, critique, or simply document the changing social life of the Ottoman capital. My argument places sexuality and morality at the heart of late-Ottoman politics, rejecting a historiography that often sees them as epiphenomenal. I emphasise that anxieties connected to public morality were not merely “repressive” but had important productive effects, shaping the norms of appropriate behaviour and sexual practice in the late-Ottoman public sphere. In studying this history, we can better understand the continuity between the late-Ottoman and Republican periods and, indeed, the bitterly conflicted terrain of gender and sexual politics in Turkey today.