Socially anxious individuals struggle with establishing and maintaining social relationships. We hypothesized that, when socially anxious, people often turn to nostalgia, which alleviates the interpersonal competence deficits that accompany social anxiety. We tested and supported this hypothesis in six studies ( N = 1,858), three preregistered. In cross-sectional Study 1, higher (compared with lower) social anxiety individuals more frequently identified interpersonal incompetence as a trigger of nostalgia. In cross-sectional Study 2, social anxiety was associated negatively with interpersonal competence, but positively with nostalgia, which in turn predicted higher interpersonal competence. In the final four studies, we tested causation. Although social anxiety reduced interpersonal competence, it also triggered nostalgia (Studies 3–3S), and nostalgia increased interpersonal competence (Studies 4–5).