In recent years there has been an increased focus on relatives of mentally vulnerable individuals. This focus indicates the importance of approaching the topic at hand in such a way that it can assist in providing a more thorough understanding of mental vulnerabilities and its effects upon relatives of those afflicted. In light of this, we have formulated a master thesis which aims to explore how it is experienced for young adults in emerging adulthood to be a relative of a mentally vulnerable parent or sibling.An initial literary search of the topic has provided insight into the pre-existing litera-ture in the field while assisting in forming the background for our understanding of the phenomenon, along with the concepts in relation to it. The method for exploring the research question of this master thesis was conducted within the frame of qualitative methodology, specifically using the method of inter-view. Three young individuals with a mentally vulnerable parent or sibling were inter-viewed in order to gain insight into their experiences as relatives in emerging adult-hood, and how it affects or is affected during these years. Through the use of thematic analysis, in regard to the collected empirical data obtained, nine themes were identified as having increased relevance with respect to understanding how individuals in emerging adulthood experience having a mentally vulnerable parent or sibling: 1) Family relationships, 2) Costs for own life, 3) Responsibility, 4) Difficult feelings, 5) Boundaries, 6) Coping, 7) Worries, 8) Secrecy and 9) Identity. This master thesis utilises two theoretical perspectives, Erikson’s theory of identity development and positioning theo-ry by Harré, with the purpose of introducing possible understandings of the empirical data. This resulted in the identification of four main areas of focus: 1) Establishment of own life, 2) Career path, 3) Romantic relationships and 4) Own vulnerability and resulting concerns.Based on the analysis and the theoretical understanding of the empirical data gathered, this master thesis concludes that having a mentally vulnerable parent or sibling will result in costs for the relatives themselves in emerging adulthood. For relatives, emerging adulthood is complicated by their life circumstances as it permeates all aspects of their lives. This can be seen in their family life, their work and education, their psychological well-being, their love life, their dreams of establishing their own family, along with their sense of self all being affected. The complications relatives experience in emerging adulthood are understood as a product of having developed a weak identi-ty due to a negative outcome of one or more developmental stages, as well as a problematic youth with limited opportunities for identity formation. Additionally, these complications may arise due to the difficult positions the relatives find themselves in and because some social expectations of relatives conflict with the expectations of emerging adults.This master thesis gives rise to multiple discussions. Firstly, the research design, and its execution is discussed. Here a critical stance has been employed when analysing the methodological choices made, especially with a focus on the validity, reliability, and generalisability of this master thesis. Secondly, the theoretical perspectives includ-ed in this master thesis are discussed, and consideration has been taken as to how the results from this thesis will contribute to pre-existing research in the field.Finally, the implications this master thesis can contribute with, both in practice, and for future research has been presented. The end goal for this master thesis is that the knowledge obtained through our research can be used to better understand the dynamics of being a relative to a mentally vulnerable parent or sibling during emerging adult-hood, and that this knowledge can be employed by those who work with these individuals in order to provide improved help and support.