We proposed that nostalgia, by virtue of its sociality, can be an indirect strategy to counteract relational deficiencies stemming from group‐based exclusion. We instructed Greek participants to recall an event in which they experienced exclusion on the basis of their nationality versus a control event. We anticipated that participants would react to group‐based exclusion with increased nostalgia. Specifically, because low attachment‐related avoidance facilitates proximity‐seeking in response to distress, we hypothesised that group‐based exclusion would increase nostalgia (a form of proximity‐seeking) more strongly when avoidance is low. Results supported this moderation hypothesis. In turn, increased nostalgia in response to group‐based exclusion predicted stronger ingroup identification. For low‐avoidants, then, group‐based exclusion fortified ingroup identification via increased nostalgia (moderated mediation).