COVID-19 lockdown has been worldwide considered one of the major collective traumatic experiences for everyone, vulnerable adolescents included. Surprisingly, however, research on the experiences of adolescent living in residential care (RC) – considered it to be particularly exposed to traumas and developmental challenges – has been underdeveloped in the pandemic scenario. Bridging this gap and drawing on a national survey with Italian adolescents living in RC, the current study examines their psychosocial wellbeing, i.e., their perceived subjective and relational wellbeing, during lockdown. In terms of subjective wellbeing, results show increased irritability, but, differently from general population, no sleep quality deterioration. In terms of relational wellbeing, we document a general sense of safeness and protection in RC, a significant sense of being listened to by caregivers, and continuity of care with professionals and keypersons. We confirm and display two distinctive effects as well: a) the “gender effect” – i.e., compared to boys, girls reported higher irritability, and b) the “length of placement in RC” effect – i.e., adolescents living in RC for more than 3 years reported increased irritability and a lower relational wellbeing, counterbalanced by a higher competence in keeping their contact with their schoolmates outside RC. Proposals for targeted psychosocial interventions, limitations and implications for future research in the developmental areas are discussed in the conclusions.