Social support at university is key for student wellbeing and retention. The majority of undergraduate students live with same-age housemates, so examining the relationship that students have with their housemates may be critical for understanding student adjustment. However, to date, social relationships within university accommodation have not been examined in detail. In the current study, N = 90 undergraduates at universities across the UK took part in an online qualitative study examining the relationships that students have with their housemates, and the role that this might play in student wellbeing. Four themes were constructed from the data using inductive qualitative content analysis: "Proximity and shared experience"; "Emotional and practical support"; "Conflict stems from disrespect"; and "Loneliness, isolation and distress." Together, the themes demonstrate the divergent impact that housemates can have on student wellbeing: they can be a source of immense support or great unhappiness. The findings could have practical implications for how to foster more positive or functional peer relationships in university accommodation (such as mediation services), which could enhance and support student wellbeing.