<p>Sexual and romantic rejection are issues that humans have faced for centuries. Recently, experiences such as these have developed into a form of identity and community rallying point. Involuntary celibates (incels) are one example of this phenomenon; however, the group have achieved notoriety for their association with violent attacks and promotion of misogyny in response to their frustration. While recent work has identified that incels suffer from more mental and relational health issues, what is left to be determined is why individuals who are experiencing romantic or sexual rejection would adopt the incel label, given the infamy of the group. Using Interpretative Phenomenological Analysis, the present study explored the psychosocial influences and drivers behind incel identity development via interviews with self-identified incels. Six superordinate themes were identified, including a history of social exclusion, blame attribution, psychosocial insights, responses to rejection, the value placed on feeling included, and the development of a (threatened) social identity. These results reveal how social rejection and exclusion impact incel identity formation suggesting that theories like interpersonal rejection theory, social identity theory, and attribution theory may help explain why some men adopt the incel label. Overall, the study highlights the complexity of the incel phenomenon and the need to provide more effective support for self-identified incels.</p>