ABSTRACTThe article explores the significance of laughter in Thomas Mann's Der Zauberberg. While laughter is a prominent feature in the novel, it has not received sufficient critical consideration either in Mann scholarship or, more generally, in studies of modernism. Through close examination of selected episodes of laughter, this study establishes the importance of laughter in the novel, both quantitatively and qualitatively. The analysis examines the extent to which the representation of laughter in the novel conforms to or deviates from recent characterisations of laughter in modernist texts. While certain interpretations of modernist laughter as disruptive and/or pathological can be applied to this text, this is not entirely true of its use in Der Zauberberg. Rather, the significance of laughter shifts constantly throughout the novel, culminating in a crisis of laughter that is part of a larger crisis of sociability and ‘Bildung’. The novel suggests that laughter formerly played a critical role in fostering communication, sociability, self‐awareness, and civility. In contrast, the crisis of laughter towards the end of the novel invites reflection on the loss of these social and humane functions. The crisis of laughter in Der Zauberberg, I argue, is of particular relevance to the interpretation of laughter in other modernist novels which engage in critical dialogue with the ‘Bildungsroman’ tradition.