Nostalgia is a common, bittersweet experience described as a sentimental longing for the past. Past research has found nostalgia to be a social emotion that increases feelings of social connectedness and motivates social engagement. Despite the prevalence of people reminiscing in conversations, few studies have studied nostalgia in a social setting. Thus, this research examined an uncharted area of nostalgia: shared nostalgia. The current work defines shared nostalgia as an experience in which nostalgia is transmitted to at least one other person or exchanged between two or more people. Study 1 investigated the prevalence and affective nature of shared nostalgia and found it is a bittersweet and common experience, even more so than reflecting on nostalgic memories individually. Based on the findings of Study 1, Studies 2-4 examined the potential social connectedness function of collaborative nostalgia, a type of shared nostalgia. Study 2 found that the desire for collaborative nostalgia is associated with high emotional closeness, emotional distance, and temporal distance to social relationships, suggesting it generally concerns a desire to connect with others. Indeed, the relationship between emotional distance and the desire for collaborative nostalgia was mediated by a motivation to connect. Studies 3 and 4 experimentally tested the relationship between collaborative nostalgia and temporal and emotional closeness. Although the manipulations failed to support the presented hypotheses, exploratory analyses provide interesting insights into shared nostalgia. In all, shared nostalgia is a crucial addition to the nostalgia literature that warrants further investigation.