Travestimento/travestitismo: Masquerade and Mischief in Boccaccio’s World examines Boccaccio’s use of masquerade to parody social conventions and invert the cultural themes characterizing fourteenth-century Italy. Its aim is to demonstrate the myriad ways in which the medieval author masks and unmasks characters—often using gender as performance—to gain access to either sublimated sexuality or forbidden power, and ultimately to reveal rather than conceal human nature. This study offers a close reading of the Ninfale fiesolano and five novellas (2.3, 2.9, 3.1, 3.2, and 4.2) of the Decameron, focusing on characters that go beyond their usual identity and/or the limits of their biological sex to occupy transgendered spaces. Today, our understanding of gender studies encompasses a far more inclusive understanding of the term “gender.” This dissertation begins with the concept that gender is fluid and performative, and that though the body may be fixed, its gender is not confined to restrictions imposed on it by society. Some of Boccaccio’s characters, accordingly, occupy multiple gendered spaces while assuming the identity of another sex, in particular Zinevra/Sicurano, the abbot/princess, and Africo (Chapters Two, Three, and Four). Although far from the transformations found in the mythological world of Ovid’s Metamorphoses, Boccaccio’s tales offer the “metamorphosis” of the masquerade, that is, a false outward show, a pretense, or façade that oftentimes is achieved through disguise or costume. My analysis considers how masquerade in this way (travestimento) — or in its more radical form of cross-dressing (travestitismo) — paradoxically offers access to the more authentic aims of the protagonists. Although critics have written on deception in the Decameron, they have not dealt thoroughly with the trope of masquerade and have altogether ignored the concept of transvestism. Travestimento/travestitismo: Masquerade and Mischief in Boccaccio’s World advances our understanding of gender and identity in Boccaccio’s work to show that his ideas may help us understand not only the Middle Ages, but also our own epoch.