Background Nursing homes (NH) for the elderly have been particularly affected by the Covid-19 pandemic mainly due to their hosted vulnerable populations and poor outbreak preparedness. In Belgium, the medical humanitarian organization Médecins Sans Frontières (MSF) implemented a support project for NH including training on infection prevention and control (IPC), (re)-organization of care, and psychosocial support for NH staff. As psychosocial and mental health needs of NH residents in times of Covid-19 are poorly understood and addressed, this study aimed to better understand these needs and how staff could respond accordingly. Methods A qualitative study adopting thematic content analysis. Eight focus group discussions with direct caring staff and 56 in-depth interviews with residents were conducted in eight purposively and conveniently selected NHs in Brussels, Belgium, June 2020. Results NH residents experienced losses of freedom, social life, autonomy, and recreational activities that deprived them of their basic psychological needs. This had a massive impact on their mental well-being expressed in feeling depressed, anxious, and frustrated as well as decreased meaning and quality of life. Staff felt unprepared for the challenges posed by the pandemic; lacking guidelines, personal protective equipment and clarity around organization of care. They were confronted with professional and ethical dilemmas, feeling 'trapped' between IPC and the residents' wellbeing. They witnessed the detrimental effects of the measures imposed on their residents. Conclusion This study revealed the insights of residents' and NH staff at the height of the early Covid-19 pandemic. Clearer outbreak plans, including psychosocial support, could have prevented the aggravated mental health conditions of both residents and staff. A holistic approach is needed in NHs in which tailor-made essential restrictive IPC measures are combined with psychosocial support measures to reduce the impact on residents' mental health impact and to enhance ...