This is a qualitative study on mental health among unaccompanied children in Swedish residential care. The purpose of the study is to increase the understanding of the work and interaction with these children for anyone that in one way or another encounters unaccompanied children in their profession. To achieve this, we examined the experiences of staff members in residential care regarding mental health among unaccompanied children, by conducting semi-structured interviews of staff members. This study includes descriptions of how the interviewees experience mental illness and what challenges and difficulties they encounter in their work. Furthermore, the study also includes factors the interviewees believe are important in promoting mental health. The results show that mental illness amongst unaccompanied children in residential care is a recurring issue. The interviewees describe that mental illness can be expressed in anxiety, aggression, depression, insomnia, self-harm, isolation and psychosomatic symptoms. Socio-cultural differences is stated in the results as a challenge in ways that the children and the staff members have different norms and values. Moreover it is also described that the children’s view on what mental illness is, how they talk about it and how they handle it, is different from what the staff are used to and can lead to misunderstandings. Furthermore the results also show that interviewees believe the main cause behind the children’s poor well-being is the challenges they meet and the pressure they feel when they arrive to a new country. Challenges and pressure such as learning a new language and integrating in a new society. The interviewees describe it as being important to support and be available for the children, and for the children to find and be part of meaningful connections. Keywords: unaccompanied children/youth/minors, mental illness, mental health, residental care homes, refugees