This dissertation examines the status of nihilism in postmodemity, focusing on its existential dimension. The theory of nihilism developed by Nietzsche gives philosophical expression to the widespread feeling that contemporary cultural conditions reduce the possibility of experiencing life as meaningful. The philosophical theory of nihilism is both a diagnosis of the problem of existential meaninglessness, and a response to this problem which attempts to overcome or attenuate it. Nietzsche’s formulation of nihilism is now over one hundred years old, but it has been taken up and altered by subsequent thinkers in the European philosophical tradition to explore the problem of meaninglessness in new ways. The first part of this thesis traces the developments in the discourse of nihilism through the works of Nietzsche, Sartre, and Heidegger, highlighting the way in which the prospect of overcoming nihilism is problematised with Heidegger’s work.The discourse of postmodernism which arose in the late twentieth century is a broad theory of the contemporary which is often thought to have strong resonances with nihilism. However, these resonances are rarely explored in detail. This dissertation aims to situate the problem of nihilism in the contemporary situation by examining the connection between nihilism and the postmodern as it emerges in the works of three influential European thinkers: Jean-François Lyotard, Jean Baudrillard, and Gianni Vattimo. It develops the hypothesis that the understanding of nihilism undergoes changes in the works of these postmodern theorists which reflect the broader “postmodern turn” in theory and culture. These changes involve, firstly, a shift in the theoretical terms in which nihilism is understood, corresponding with the wider move away from phenomenology and existentialism towards post-structuralism and hermeneutic ontology. Secondly, these changes correspond with the postmodern view of contemporary culture as marked by widespread social fragmentation and the loss of faith in historical progress. These themes merge to form an understanding of nihilism in the postmodern situation as characterised by the loss of hope that existential meaninglessness can be overcome, either through individual experience, or through the modern dream of progressive social emancipation. Lyotard, Baudrillard, and Vattimo each advance arguments which deepen the problem of overcoming nihilism announced by Heidegger.It is argued, however, that these postmodern theorists of nihilism usefully contribute to both our understanding of the problem of meaning in the current situation, and the possibilities for responding to it. Against the common view that postmodern theory simply contributes to nihilism, this thesis demonstrates that Lyotard, Baudrillard, and Vattimo each develop strong and coherent responses to nihilism. Aware that attempts to directly and decisively overcome nihilism fall into an aporetic impasse, these postmodernists develop strategies which respond to nihilism without seeking to overcome it, thus avoiding this impasse. As such, they calibrate their responses to the specific needs imposed by the postmodern situation. Despite the strengths of these responses, however, it is argued that the postmodern theorists of nihilism do not adequately respond to all aspects of the nihilism they diagnose: they fail to deal with the feelings of meaninglessness arising from the contingency of contemporary life which was the central concern of existentialists, and which are arguably exacerbated in postmodernity.