This study applies reader-response and reception theory to the troba cazurra lyric of the Libro de buen amor. It first reviews the nature of allegory and parody in medieval literature and the existing allegorical and parodic interpretations of the lyric. The study then describes reader response and reception theory, and justifies the validity of the application of this theory to the Libro. The reactions of four actual and two imaginary audiences to the lyric are hypothesized; in every case, the parodic interpretation of the lyric is preferred to the allegorical interpretation. The underlying nature of medieval parody, the difficulty of the ethical choice that the lyric asks the reader to make, and the unanimous reaction of the audiences examined all support and justify the lyric's parodic interpretation.