Adolescents living in residential youth care (RYC) are at risk for disadvantaged social relationships, which in turn present a risk factor for increased loneliness. Social relationships of Slovenian adolescents aged 15-18 years and living in RYC group homes (N = 51) or in their primary families (N = 100) were investigated by relying on the social convoy framework. The participants also provided self-reports on the Revised UCLA Loneliness scale. Results revealed substantial differences between the two groups of adolescents in the structure (number of members, frequency of contact), function (perceived support) and quality (satisfaction with relationships) of their social convoys reflecting less favourable social relationships among RYC youth compared to the general population youth. These differences were especially noticeable regarding their relationships with parents. Furthermore, the RYC youth listed educational workers as members of their social convoys more often, underscoring the important role of RYC staff. Unexpectedly, the two groups of adolescents did not differ in their reports of subjectively experienced loneliness. Nonetheless, the quantitative and even more so the qualitative characteristics of adolescents' social convoys correlated with feelings of loneliness, highlighting the protective role of supportive social relationships.