Both homelessness and loneliness are pervasive in North America. In this study, the author compared the causes of the loneliness experienced by young homeless youth (n = 113) with that of counterparts in the general population (n = 211) who answered a 30-item yes-no questionnaire. The results identified 5 causes of loneliness: personal inadequacy, developmental deficits, unfulfilling intimate relationships, relocation or significant separations, and social marginality. The results indicated that the causes of loneliness in young homeless youth are significantly different from those of the general population.