Evaluating Andreas Huyssen’s claim that “mass culture has always been the hidden subtext of the modernist project,” this paper examines Nezihe Muhiddin’s İstanbul’da bir Landru (A Landru in Istanbul, 1934) in light of the modernism and mass culture debates of the late twentieth century. Taking its title character from Henri Landru, the French serial killer who seduced and murdered ten women he met via advertisements in the lonely hearts section of Parisian newspapers, Muhiddin ’s novella follows the relationship between Nazlı, a young Turkish princess, and Nils, a Danish artist living in Turkey. When Nazlı discovers that Nils is the killer of five Istanbul women, he is revealed as the Landru of Istanbul. The novella’s use of gothic literary tropes and the presence of Landru, who was fetishized in press coverage of his murder trial, both point to Muhiddin’s familiarity with the popular literary conventions and mass media culture of Europe. Yet, Muhiddin’s implementation of the formal conventions of mass culture within the novella suggests a politically subversive intent that highlights and critiques the subordinate position of women within Turkish society, an act that aligns her writing with the modernist literary experiments of women writers in the Anglophone context such as Rebecca West and Virginia Woolf. This paper argues that Muhiddin’s novella is an extension of her feminist political vision, and as such sheds a complicated light on the twentieth century debates over the separation between a mass culture defined as feminine, and a modernist literary culture associated with a male elite. In a country where literacy was largely a skill of the urban and male population, and was estimated at between 10 and 15 percent of the population between 1927 and 1933, how can one understand the idea of mass literature as a feminine endeavor in Turkey? Given the novel’s status in Turkey as a civilizing instrument within the discourse of Westernizing reform, how could Muhiddin’s novella be situated within larger nineteenth and twentieth century discourses that link mass literature to the decline of civilization and culture via capitalism? Furthermore, given Muhiddin’s leadership of the Osmanlı Kadın Fırkası (Ottoman Women’s Party), her editorship of Türk Kadını, and her extensive activism for women’s rights, how might her political roles be understood to inform and engage with her authorship of women’s fantasy fiction? Finally, what light can Muhiddin’s novella shed on the modernist project in Turkey?