Alexander Zemlinsky's one-act opera A Florentine Tragedy (1917), based on Oscar Wilde's play of the same title, features an erotic triangle – a woman, her husband and her lover – that erupts into violence, murder and a shocking dramatic reversal at the end. Throughout the drama, the character of the woman is a passive mirror in whose eyes the male characters see their own idealised images. The marginalised subject-position of the woman, however, reveals the pivotal role of the feminine in the narcissistic constructions of male desire and the male self. At the same time, however, this reading enables an interpretation of the drama as a project for conceptualising another marginal subjectivity: that of the homosexual male. Drawing on Eve Sedgwick's and Kaja Silverman's theories, the article explores first the complex dynamics of the triangle at the centre of the drama, and then the implications of a Freudian triangular model of male homosexual subjectivity as constituted through narcissistic object-choice. The homoerotic subtext of Wilde's play is revealed partly through the ambiguities of the woman's position in her connections with each of the men, a role that is seen more clearly in terms of their bonds with each other. This subtext is also implicit in the typically Wildean eroticisation of commerce and commercialisation of eros, through which the men engage in relations highly nuanced by erotically inflected language. Most intriguing is the way the male homosocial reading of the drama is supported by the motivic-dramatic structure of Zemlinsky's opera, as suggested by a new interpretation of the ambiguous musical motifs of ‘love’ and ‘death’ that permeate the opera's most crucial scenes.