One of the important areas of comparative literature is the parallelism of religious narratives and literary texts. Medieval literature, due to religious dominance, was the main arena for the emergence of literature inspired by religious narratives. The story of Joseph and Zuleikha, as one of the most important religious narratives, has been adapted in various forms in different periods with diverse themes of brotherhood, the pain of separation, love and betrayal, chastity, and exile. Boccaccio - one of the most famous storytellers of the late Middle Ages - created a story in the Decameron, influenced by this narrative, which in various ways can be studied in comparison with the story of Joseph and Zuleikha. This research, which was conducted with reference to library sources and a comparative-analytical method, found ten parallels with the narrative of Joseph and Zuleikha in the areas of incident, characterization, conflict, and resolution in the story of "The Queen's Betrayal" from the Decameron. In both narratives, the king's advisor is perfection and outward charm. The king's wife falls in love with the general. The chaste general rejects the queen's offer of betrayal. and through a long series of events, the general rises to a worthy position again. The result is that the themes of those Old Testament narratives that had suitable narrative potential for adaptation and storytelling have been reproduced as fictional material in a new genre in various literary periods - especially the late Middle Ages. The Decameron is a prominent example of this.